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Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Impacts of Ethanol on Anaerobic Production of Tert-Butyl Alcohol (TBA) from Methyl Tert-Butyl Ether (MTBE) in Groundwater  

E-Print Network [OSTI]

Methyl Tert-Butyl Ether (MTBE) in Groundwater P.I. names,Methyl tert-butyl ether (MTBE) is a contaminant of concernsubsurface environments. MTBE appears to be degraded readily

Scow, K M; MacKay, Douglas

2008-01-01T23:59:59.000Z

2

Treatment of Methyl tert-Butyl Ether Vapors in Biotrickling Filters. 2.  

E-Print Network [OSTI]

vapors of methyl tert-butyl ether (MTBE), a gasoline additive of great environmental concern MTBE treatment are discussed. Introduction The rapidly rising number of reports of groundwater con- taminated with the gasoline additive methyl tert-butyl ether (MTBE) has raised concerns about its

3

Environmental Microbiology (2001) 3(6), 407416 Methyl tert-butyl ether (MTBE) degradation by a  

E-Print Network [OSTI]

Environmental Microbiology (2001) 3(6), 407±416 Methyl tert-butyl ether (MTBE) degradation of California, Riverside, Riverside, CA 92521, USA. Summary The widespread use of methyl tert-butyl ether (MTBE is often proposed as the most promising alter- native after treatment. However, MTBE biodegradation appears

4

Oxidation of methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) by ozone and combined ozone/hydrogen peroxide  

SciTech Connect (OSTI)

The aim of this work was to study the reaction of ozone and combined ozone/hydrogen peroxide on oxygenated additives such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) in dilute aqueous solution using controlled experimental conditions. Experiments conducted in a semi-continuous reactor with MTBE and ETBE in combination (initial concentration: 2 mmol/L of each) showed that ETBE was better eliminated than MTBE with both ozone and combined O[sub 3]/H[sub 2]O[sub 2]. batch experiments led to the determination of the ratio of the kinetic constants for the reaction of OH[degree]-radical with MTBE and ETBE (k[sub OH[degree]/ETBE]/k[sub OH[degree]//MTBE] = 1.7). Tert-butyl formate and tert-butyl acetate were identified as the ozonation byproducts of MTBE an ETBE, respectively, while tert-butyl alcohol was found to be produced during the ozonation of both compounds. 10 refs., 10 figs., 1 tab.

Leitner, N.K.V.; Papailhou, A.L.; Croue, J.P.; Dore, M. (Univ. de Poitiers (France)); Peyrot, J. (British Petroleum, Harfleur (France))

1994-01-01T23:59:59.000Z

5

IDENTIFYING THE USAGE PATTERNS OF METHYL TERT-BUTYL ETHER (MTBE) AND OTHER OXYGENATES IN GASOLINE USING GASOLINE  

E-Print Network [OSTI]

IDENTIFYING THE USAGE PATTERNS OF METHYL TERT-BUTYL ETHER (MTBE) AND OTHER OXYGENATES IN GASOLINE USING GASOLINE SURVEYS By Michael J. Moran, Rick M. Clawges, and John S. Zogorski U.S. Geological Survey 1608 Mt. View Rapid City, SD 57702 Methyl tert-butyl ether (MTBE) is commonly added to gasoline

6

Multiple steady states during reactive distillation of methyl tert-butyl ether  

SciTech Connect (OSTI)

This paper presents results of computer simulations of the synthesis of methyl tert-butyl ether (MTBE) in a fixed-bed reactor and in a reactive distillation column. These calculations clearly showed the advantages of MTBE synthesis in a catalytic distillation tower. Furthermore, the computer simulations showed that multiple steady states may occur in the reactive distillation column during MTBE synthesis in a broad range of operating conditions. An analysis of some sensitivity studies is presented.

Nijhuis, S.A. (Univ. of Amsterdam (Netherlands). Chemical Engineering Dept.); Kerkhof, F.P.J.M.; Mak, A.N.S. (Comprimo Engineers and Contractors, Amsterdam (Netherlands))

1993-11-01T23:59:59.000Z

7

Measurement of methyl-tert-butyl-ether (MTBE) in raw drinking water  

SciTech Connect (OSTI)

In order to assess the pathways for human exposure to methyl-tert-butyl-ether (MTBE) and to understand the extent of MTBE contamination in watersheds, a purge and trap gas chromatographic mass spectrometric method to measure part-per-trillion (ppt) concentrations of MTBE in environmental waters was developed. A variety of California's raw drinking waters were analyzed. No detectable MTBE was found in deep groundwater (>1000 feet). However shallow groundwater ({approx}250 feet) contained MTBE concentrations of non-detect to 1300 ppt. MTBE concentrations measured in rivers and lakes ranged from non-detect to 3500 ppt. East (San Francisco) Bay area rain water contained approximately 80 ppt MTBE.

Davisson, M L; Koester, C J; Moran, J E

1999-10-14T23:59:59.000Z

8

Determination of methyl tert. butyl ether (MTBE) in gasoline  

SciTech Connect (OSTI)

A GLC-acid extraction method is described for the determination of MTBE in gasolines. The method consists of a programmed GLC analysis starting at about room temperature conducted before and after extraction with cold 85% phosphoric acid. This treatment results in the preferential solubility of ethers and other oxygenated compounds while minimizing the reaction of olefins and aromatics which may be present in the gasolines. Plotting various known concentrations of MTBE in gasolines against the concentrations determined in the same samples by the authors methodology results in a straight line relationship. The concentration of MTBE in any sample of gasoline may thus be determined using their GLC-extraction procedure and the calibration line. The analysis can accommodate a wide choice of standard GLC columns and programs. 2 refs., 1 fig., 1 tab.

Feldman, J.; Orchin, M. (Univ. of Cincinnati, OH (United States))

1993-02-01T23:59:59.000Z

9

Review of the environmental behavior and fate of methyl tert-butyl ether  

SciTech Connect (OSTI)

A review of pertinent equations and current research indicates that when gasoline oxygenated with methyl tert-butyl ether (MTBE) comes into contact with water, large amounts of MTBe can dissolve. At 25 C, the water solubility of MTBE is about 5,000 mg/L for a gasoline that is 10% MTBE by weight, whereas for a nonoxygenated gasoline, the total hydrocarbon solubility in water is typically about 120 mg/L. Methyl tert-butyl ether sorbs only weakly to subsurface solids; therefore, sorption does not substantially retard the transport of MTBE by ground water. In addition, MTBE generally resists biodegradation in ground water. The half-life of MTBE in the atmosphere can be as short as 3 d in a regional airshed. In the air, MTBE tends to partition into atmospheric water, including precipitation. However, the washing out of gas-phase MTBE by precipitation will not, by itself, greatly alter the gas-phase concentration of the compound in the air. The partitioning of MTBE to precipitation can nevertheless result in concentrations as high as 3 {micro}g/L or more in urban precipitation and can contribute to the presence of MTBE in surface and ground water.

Squillace, P.J.; Zogorski, J.S. [Geological Survey, Rapid City, SD (United States); Pankow, J.F. [Oregon Graduate Inst. of Science and Technology, Beaverton, OR (United States). Dept. of Environmental Science and Engineering; Korte, N.E. [Oak Ridge National Lab., TN (United States). Environmental Science Div.

1997-09-01T23:59:59.000Z

10

Why methyl tert-butyl ether production by reactive distillation may yield multiple solutions  

SciTech Connect (OSTI)

This paper presents an explanation of why methyl tert-butyl ether (MTBE) production by reactive distillation may yield multiple solutions. Widely different composition profiles and conversions may, as already reported by Krishna and others, results with identical column specifications, depending on the initial estimates provided. A hypothesis yielding a qualitative understanding of this phenomenon has been developed. The inert n-butene plays a key role in the proposed explanation: As the reaction mixture is diluted with n-butene, the activity coefficient of methanol increases substantially and the temperature decreases. This dilution has a profound effect on the equilibrium conversion, enabling MTBE to escape from the reactive zone without decomposition. When methanol is fed below or in the lower part of the reactive zone of the column, the ``lifting capacity`` of the minimum boiling point MTBE-methanol azeotrope will also be important.

Hauan, S.; Hertzberg, T.; Lien, K.M. [Univ. of Trondheim (Norway)

1995-03-01T23:59:59.000Z

11

Exposure to methyl tert-butyl ether and benzene among service station attendants and operators  

SciTech Connect (OSTI)

Concerns for atmospheric pollution from auto exhaust have led to the blending of {open_quotes}oxygenates{close_quotes} with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is currently required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the motor fuel. Amendments to the Clean Air Act may expand this requirement to as many as 44 other areas of the United States in the near future. In consideration of the magnitude of potential uncontrolled exposures from its extensive use and a related concern involving the potential influence of MTBE blending on exposures to other constituents of gasoline (particularly benzene), an evaluation of exposures among service station attendants and operators was undertaken at the request, and in cooperation with, the American Petroleum Institute during the latter part of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with regard to MTBE use and exposure potential: (a) service stations that do not use MTBE or use it only as an octane enhancer, (b) service stations with seasonal requirements to use 12-15% MTBE (the Denver, Colorado, and Phoenix, Arizona, metropolitan areas), and (c) service stations equipped with stage II (active) vapor recovery systems (several coastal areas, most notably Southern California). 4 refs., 4 tabs.

Hartle, R. [National Inst. for Occupational Safety and Health, Cincinnati, OH (United States)

1993-12-01T23:59:59.000Z

12

Reaction calorimetry study of the liquid-phase synthesis of tert-butyl methyl ether  

SciTech Connect (OSTI)

The liquid-phase addition of methanol to isobutene to give tert-butyl methyl ether (MTBE) on the ion-exchange resin Lewatit K2631 has been studied in a calorimetric reactor. Heat capacity of MTBE and enthalpy of the MTBE synthesis reaction in the temperature range 312--333 K have been determined. MTBE heat capacity in the liquid phase has been found to obey the equation c[sub P] (J/mol[center dot]K) = 472.34 [minus] 2.468(T/K) + 0.005071(T/K)[sup 2]. At 298 K the standard molar reaction enthalpy is [Delta]H[degree] = [minus]33.8 kJ/mol. A method to estimate apparent activation energies from heat flow rate in a given reaction has been developed and proved to be valid for the MTBE synthesis. Using this method, an apparent activation energy of 91.1--95.2 kJ/mol is calculated. A [minus]3.8 kJ/mol value has been found for the adsorption enthalpy of methanol on the ion-exchange resin Lewatit K2631 by a combination of reaction calorimetry and thermogravimetry. This allows the calculation of an activation energy on the gel phase of the resin of 91 kJ/mol.

Sola, L.; Pericas, M.A.; Cunill, F.; Iborra, M. (Univ. de Barcelona (Spain). Dept. d'Enginyeria Quimica)

1994-11-01T23:59:59.000Z

13

alkyl tert-butyl ether: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

by Fusarium solani CiteSeer Summary: Fusarium solani degraded methyl tert-butyl ether (MTBE) and other oxygenated compounds from gasoline including tert-butyl alcohol (TBA). The...

14

LIDEM unit for the production of methyl tert-butyl ether from butanes  

SciTech Connect (OSTI)

One of the basic problems in the production of motor fuels is how to obtain high-octane unleaded gasolines that will meet today`s ecological requirements. The term {open_quotes}reformulated gasolines{close_quotes} has come into general use throughout the world to denote fuels with a certain chemical composition. These gasolines consist of preselected components; as shown by worldwide experience, they must include oxygen-containing compounds that are distinguished by high octane numbers and low reactivities. Standards in effect in the United States, Japan, and certain Western European countries require that automotive gasolines must contain at least 2-4% by weight of oxygen-containing compounds (calculated as oxygen). In the last 15 years, in order to meet these requirements, production has been set up in various countries for the manufacture of high-octane oxygen-containing components known as oxygenates. The most common of these is methyl tert-butyl ether (MTBE), obtained by etherification of isobutene by methanol. Process technology developed by this last organization was used as the basis for constructing a unit in the Nizhnekamskneftekhim Production Association and at the Mazheikyai Petroleum Refinery in Lithuania. MTBE production has been held back mainly by a shortage of isobutene, which is obtained mainly from butane-butene cuts produced in cat crackers. In order to alleviate this shortage, it has been proposed that MTBE should be obtained from saturated C{sub 4} hydrocarbons that are recovered in processing oilfield associated gas, and also in the refinery from primary distillation units, catalytic reformers, and hydrocrackers. A working design was developed in 1991-1992 by Lengiproneftekhim for a basically new combination unit designed for the processing of saturated C{sub 4} hydrocarbons, which has been termed the LIDEM unit (Leningrad - isomerization - dehydrogenation - MTBE).

Rudin, M.G.; Zadvornov, M.A.

1994-09-01T23:59:59.000Z

15

Biodegradation of methyl tert-butyl ether by a bacterial pure culture  

SciTech Connect (OSTI)

A bacterial strain, PM1, which is able to utilize methyl tert-butyl ether (MTBE) as its sole carbon and energy source, was isolated from a mixed microbial consortium in a compost biofilter capable of degrading MTBE. Initial linear rates of MTBE degradation by 2 x 10{sup 6} cells ml{sup {minus}1} were 0.07, 1.17, and 3.56 {mu}g ml{sup {minus}1} h{sup {minus}1} for initial concentrations of 5, 50, and 500 {mu}g MTBE ml{sup {minus}1}, respectively. When incubated with 20 {mu}g of uniformly labeled [{sup 14}C]MTBE ml{sup {minus}1}, strain PM1 converted 46% to {sup 14}CO{sub 2} and 19% to {sup 14}C-labeled cells within 120 h. This yield is consistent with the measurement of protein accumulation at different MTBE concentrations from which was estimated a biomass yield of 0.18 of cells mg MTBE{sup {minus}1}. Strain PM1 was inoculated into sediment core material collected from a contaminated groundwater plume at Port Hueneme, California, in which there was no evidence of MTBE degradation. Strain PM1 readily degraded 20 {micro}g of MTBE ml{sup {minus}1} added to the core material. The rate of MTBE removal increased with additional inputs of 20 {micro}g of MTBE ml{sup {minus}1}. These results suggest that PM1 has potential for use in the remediation of MTBE-contaminated environments.

Hanson, J.R.; Ackerman, C.E.; Scow, K.M.

1999-11-01T23:59:59.000Z

16

active methyl tert-butyl: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

by Fusarium solani CiteSeer Summary: Fusarium solani degraded methyl tert-butyl ether (MTBE) and other oxygenated compounds from gasoline including tert-butyl alcohol (TBA). The...

17

Methyl tert-butyl ether (MTBE) is a volatile organic com-pound (VOC) derived from natural gas that is added to gas-  

E-Print Network [OSTI]

Methyl tert-butyl ether (MTBE) is a volatile organic com- pound (VOC) derived from natural gas Water in Urban and Agricultural Areas made from methanol, which is derived primarily from natural gas that is added to gas- oline either seasonally or year round in many parts of the United States to increase

18

Kinetics and modeling of mixture effects during complete catalytic oxidation of benzene and methyl tert-butyl ether  

SciTech Connect (OSTI)

The performance of a catalytic incinerator depends on the nature of the compounds being oxidized and cannot be predicted simply by knowing the performance of the incinerator with pure-component model compounds. Considering the importance of mixture effects, an attempt was made to develop a combined model to predict the conversion when benzene and methyl tert-butyl ether (MTBE) are simultaneously oxidized. Complete catalytic oxidation of benzene and MTBE, singly and in mixtures, was investigated over a platinum catalyst. No inhibition effects were seen with benzene, but MTBE conversion was distinctly inhibited by benzene. A Mars-van Krevelen rate model was used to explain the results. Model parameters were obtained from pure-component experiments and then incorporated into a multicomponent model without any adjustment or additional rate parameters. The multicomponent model was able to predict the conversion of benzene and MTBE oxidation in the binary mixture using the pure-component data without adjustable parameters.

Dangi, S.; Abraham, M.A. [Univ. of Tulsa, OK (United States). Dept. of Chemical Engineering] [Univ. of Tulsa, OK (United States). Dept. of Chemical Engineering

1997-06-01T23:59:59.000Z

19

Control Study of Ethyl tert-Butyl Ether Reactive Distillation Muhammad A. Al-Arfaj  

E-Print Network [OSTI]

-butyl ether (ETBE) for gasoline blending as a replacement for methyl tert-butyl ether (MTBE) because and be blended with ETBE in the gasoline pool. Even for neat operation, if the conversion is low, the unconverted

Al-Arfaj, Muhammad A.

20

Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. [801Methyl tert-butyl ether  

SciTech Connect (OSTI)

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: (1) Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. (2) Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. (3) Addition of methanol to slurry phase FT synthesis making iso-olefins. During the sixth quarter we completed the construction of the slurry bubble column reactor (SBCR), conducted initial shake-down experiments in a cold-flow mode, and finalized the selection process of the acid catalysts for conversion of syngas-produced alcohols and isobutylene to MTBE (scheme 2). Tasks 3, 4, and 5 are awaiting complete implementation of the SBCR system.

Marcelin, G.

1992-06-24T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Kinetics and mechanism of the sonolytic destruction of methyl tert-butyl ether by ultrasonic irradiation in the presence of ozone  

SciTech Connect (OSTI)

The kinetics and mechanism of the sonolytic degradation of methyl tert-butyl ether (MTBE) have been investigated at an ultrasonic frequency of 205 kHz and power of 200 W L{sup {minus}1}. The observed first-order degradation rate constant for the loss of MTBE increased from 4.1 {times} 10{sup {minus}4} s{sup {minus}1} to 8.5 {times} 10{sup {minus}4} s{sup {minus}1} as the concentration of MTBE decreased from 1.0 to 0.01 mM. In the presence of O{sub 3}, the sonolytic rate of destruction of MTBE was accelerated substantially. The rate of MTBE sonolysis with ozone was enhanced by a factor of 1.5--3.9 depending on the initial concentration of MTBE. tert-Butyl formate, tert-butyl alcohol, methyl acetate, and acetone were found to be the primary intermediates and byproducts of the degradation reaction with yields of 8, 5, 3, and 12%, respectively. A reaction mechanism involving three parallel pathways that include the direct pyrolytic decomposition of MTBE, the direct reaction of MTBE with ozone, and the reaction of MTBE with hydroxyl radical is proposed.

Kang, J.W. [Yonsei Univ., Wonju (Korea, Republic of). Dept. of Industrial Environment and Health] [Yonsei Univ., Wonju (Korea, Republic of). Dept. of Industrial Environment and Health; Hoffmann, M.R. [California Inst. of Tech., Pasadena, CA (United States). W.M. Keck Labs.] [California Inst. of Tech., Pasadena, CA (United States). W.M. Keck Labs.

1998-10-15T23:59:59.000Z

22

Whole-genorne analysis of the methyl tert-butyl ether-degrading beta-proteobacterium Methylibium petroleiphilum PM1  

SciTech Connect (OSTI)

Methylibium petroleiphilum PM1 is a methylotroph distinguished by its ability to completely metabolize the fuel oxygenate methyl tert-butyl ether (MTBE). Strain PM1 also degrades aromatic (benzene, toluene, and xylene) and straight-chain (C, to C,,) hydrocarbons present in petroleum products. Whole-genome analysis of PM1 revealed an similar to 4-Mb circular chromosome and an similar to 600-kb megaplasmid, containing 3,831 and 646 genes, respectively. Aromatic hydrocarbon and alkane degradation, metal resistance, and methylotrophy are encoded on the chromosome. The megaplasmid contains an unusual t-RNA island, numerous insertion sequences, and large repeated elements, including a 40-kb region also present on the chromosome and a 29-kb tandem repeat encoding phosphonate transport and cobalamin biosynthesis. The megaplasmid also codes for alkane degradation and was shown to play an essential role in MTBE degradation through plasmid-curing experiments. Discrepancies between the insertion sequence element distribution patterns, the distributions of best BLASTP hits among major phylogenetic groups, and the G+C contents of the chromosome (69.2%) and plasmid (66%), together with comparative genome hybridization experiments, suggest that the plasmid was recently acquired and apparently carries the genetic information responsible for PM1's ability to degrade MTBE. Comparative genomic hybridization analysis with two PM1-like MTBE-degrading environmental isolates (similar to 99% identical 16S rRNA gene sequences) showed that the plasmid was highly conserved (ca. 99% identical), whereas the chromosomes were too diverse to conduct resequencing analysis. PM1's genome sequence provides a foundation for investigating MTBE biodegradation and exploring the genetic regulation of multiple biodegradation pathways in M. petroleiphilum and other MTBE-degrading beta-proteobacteria.

Kane, Staci R. [Lawrence Livermore National Laboratory (LLNL); Chakicherla, Anu Y. [Lawrence Livermore National Laboratory (LLNL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Schmidt, Radomir [University of California, Davis; Shin, M [U.S. Department of Energy, Joint Genome Institute; Legler, Tina C. [Lawrence Livermore National Laboratory (LLNL); Scow, Kate M. [University of California, Davis; Larimer, Frank W [ORNL; Lucas, Susan [Joint Genome Institute, Walnut Creek, California; Richardson, P M [U.S. Department of Energy, Joint Genome Institute; Hristova, Krassimira R. [University of California, Davis

2007-03-01T23:59:59.000Z

23

Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint  

SciTech Connect (OSTI)

The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weighted average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.

Tan, C.; Ong, H.Y.; Kok, P.W. [and others

1996-12-31T23:59:59.000Z

24

Treatment of Methyl tert-Butyl Ether Contaminated Water Using a Dense  

E-Print Network [OSTI]

-butyl ether (MTBE) in a dense medium plasma (DMP) reactor utilizing gas chromatog- raphy-massspectrometryandgaschromatography-thermal conductivity techniques. A rate law is developed for the removal of MTBE from an aqueous solution in the DMP. The oxidation products from the treatment of MTBE-contaminated water in the DMP reactor were found

Dandy, David

25

Manipulation of the HIF–Vegf pathway rescues methyl tert-butyl ether (MTBE)-induced vascular lesions  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE) has been shown to be specifically anti-angiogenic in piscine and mammalian model systems at concentrations that appear non-toxic in other organ systems. The mechanism by which MTBE targets developing vascular structures is unknown. A global transcriptome analysis of zebrafish embryos developmentally exposed to 0.00625–5 mM MTBE suggested that hypoxia inducible factor (HIF)-regulated pathways were affected. HIF-driven angiogenesis via vascular endothelial growth factor (vegf) is essential to the developing vasculature of an embryo. Three rescue studies were designed to rescue MTBE-induced vascular lesions: pooled blood in the common cardinal vein (CCV), cranial hemorrhages (CH), and abnormal intersegmental vessels (ISV), and test the hypothesis that MTBE toxicity was HIF–Vegf dependent. First, zebrafish vegf-a over-expression via plasmid injection, resulted in significantly fewer CH and ISV lesions, 46 and 35% respectively, in embryos exposed to 10 mM MTBE. Then HIF degradation was inhibited in two ways. Chemical rescue by N-oxaloylglycine significantly reduced CCV and CH lesions by 30 and 32% in 10 mM exposed embryos, and ISV lesions were reduced 24% in 5 mM exposed zebrafish. Finally, a morpholino designed to knock-down ubiquitin associated von Hippel–Lindau protein, significantly reduced CCV lesions by 35% in 10 mM exposed embryos. In addition, expression of some angiogenesis related genes altered by MTBE exposure were rescued. These studies demonstrated that MTBE vascular toxicity is mediated by a down regulation of HIF–Vegf driven angiogenesis. The selective toxicity of MTBE toward developing vasculature makes it a potentially useful chemical in the designing of new drugs or in elucidating roles for specific angiogenic proteins in future studies of vascular development. - Highlights: • Global gene expression of MTBE exposed zebrafish suggested altered HIF1 signaling. • Over expression of zebrafish vegf-a rescues MTBE-induced vascular lesions. • Inhibiting PHD or knocking down VHL rescues MTBE-induced vascular lesions. • HIF1-Vegf driven angiogenesis is a target for MTBE vascular toxicity.

Bonventre, Josephine A., E-mail: josephine.bonventre@oregonstate.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States); Oregon State University, Department of Environmental and Molecular Toxicology, 1011 Agricultural and Life Sciences Bldg, Corvallis, OR 97331 (United States); Kung, Tiffany S., E-mail: tiffany.kung@rutgers.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States); White, Lori A., E-mail: lawhite@aesop.rutgers.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States); Cooper, Keith R., E-mail: cooper@aesop.rutgers.edu [Rutgers, The State University of New Jersey, Joint Graduate Program in Toxicology, 170 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rutgers, The State University of New Jersey, Department of Biochemistry and Microbiology, 76 Lipman Dr., New Brunswick, NJ 08901 (United States)

2013-12-15T23:59:59.000Z

26

Determination of Methyl tert-Butyl Ether and tert-Butyl Alcohol in Water by Solid-Phase Microextraction/Head Space Analysis in Comparison to EPA Method 5030/8260B  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE) is now one of the most common groundwater contaminants in the United States. Groundwater contaminated with MTBE is also likely to be contaminated with tert-butyl alcohol (TBA), because TBA is a component of commercial grade MTBE, TBA can also be used as a fuel oxygenate, and TBA is a biodegradation product of MTBE. In California, MTBE is subject to reporting at concentrations greater than 3 {micro}g/L. TBA is classified as a ''contaminant of current interest'' and has a drinking water action level of 12 {micro}g/L. In this paper, we describe the development and optimization of a simple, automated solid phase microextraction (SPME) method for the analysis of MTBE and TBA in water and demonstrate the applicability of this method for monitoring MTBE and TBA contamination in groundwater, drinking water, and surface water. In this method, the headspace (HS) of a water sample is extracted with a carboxen/polydimethylsiloxane SPME fiber, the MTBE and TBA are desorbed into a gas chromatograph (GC), and detected using mass spectrometry (MS). The method is optimized for the routine analysis of MTBE and TBA with a level of quantitation of 0.3 {micro}g/L and 4 {micro}g/L, respectively, in water. MTBE quantitation was linear for over two orders of concentration (0.3 {micro}g/L -80 {micro}g/L). TBA was found to be linear within the range of 4 {micro}g/L-7,900 {micro}g/L. The lower level of detection for MTBE is 0.03 {micro}g/L using this method. This SPME method using headspace extraction was found to be advantageous over SPME methods requiring immersion of the fiber into the water samples, because it prolonged the life of the fiber by up to 400 sample analyses. This is the first time headspace extraction SPME has been shown to be applicable to the measurement of both MTBE and TBA at concentrations below regulatory action levels. This method was compared with the certified EPA Method 5030/8260B (purge-and-trap/GC/MS) using split samples from laboratory bioreactors treating MTBE contaminated water and applied to environmental samples collected throughout the East Bay area of California. Results from the SPME-HS/GC/MS method were directly comparable to the EPA Method 5030/8260B. This method provides an simple, inexpensive, accurate, and sensitive alternative to EPA Method 5030/8260B for the analysis of MTBE and TBA in water samples.

Oh, Keun-Chan; Stringfellow, William T.

2003-10-02T23:59:59.000Z

27

Treatment of methyl tert-butyl ether vapors in a biotrickling filters. 2. Analysis of the rate-limiting step and behavior under transient conditions  

SciTech Connect (OSTI)

Detailed experiments were performed with gas phase biotrickling filters treating vapors of methyl tert-butyl ether (MTBE), a gasoline additive of great environmental concern. A particular emphasis was placed on the analysis of the rate-limiting step, and it was found that the process was mostly limited by the biological reaction rather than by mass transfer. Further experiments involved the study of the dynamic behavior of the biotrickling filters under simulated field conditions. In all cases, the biotrickling filters adapted rapidly to the new conditions, and new steady states were obtained within hours. The relevance of the results and the implications as far as implementation of biotrickling filters for field MTBE treatment are discussed.

Fortin, N.Y.; Deshusses, M.A. [Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering] [Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering

1999-09-01T23:59:59.000Z

28

Cytotoxic and DNA-damaging effects of methyl tert-butyl ether and its metabolites on HL-60 cells in vitro  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE) is a widely used oxygenate in unleaded gasoline; however, few studies have been conducted on the toxicity of this compound. This study evaluates the cytotoxic and DNA-damaging effects of MTBE and its metabolites in a human haemopoietic cell line, HL-60. The metabolites of MTBE studied include tertiary butyl alcohol (TBA), {alpha}-hydroxyisobutyric acid (HIBA), and formaldehyde. Comet assay is used to assess DNA damage, and the cytotoxicity is investigated by lactate dehydrogenease (LDH) release. The results show no significant cytotoxic effects of MTBE, TBA, and HIBA over a concentration ranging from 1 to 30 mM. Formaldehyde, in contrast, causes a substantial LDH release at a concentration of 5 {mu}M. Hydrogen peroxide, a known oxidative agent, at concentrations ranging from 10 to 100 {mu}M, produces a significant dose-related increase in DNA damage, whereas a much higher concentration of MTBE (1 to 30 mM) is required to produce a similar observation. The genotoxic effects of TBA and HIBA appear to be identical to that of MTBE. Conversely, DNA damage is observed for formaldehyde at a relatively low concentration range (5 to 100 {mu}M). These findings suggest that MTBE and its metabolites, except formaldehyde, have relatively low cytotoxic and genotoxic effects. 16 refs., 4 figs.

Tang, G.H. [Xian Medical Univ. (China); Shen, Y.; Shen, H.M. [National Univ. of Singapore (Singapore)] [and others

1996-12-31T23:59:59.000Z

29

Treatment of methyl tert-butyl ether vapors in biotrickling filters. 1. Reactor startup, steady-state performance, and culture characteristics  

SciTech Connect (OSTI)

An aerobic microbial consortium able to biodegrade methyl tert-butyl ether (MTBE) was enriched in two waste air biotrickling filters after continuous operation for 6 months. After this acclimation phase, the two laboratory-scale biotrickling filters were able to degrade up to 50 g of MTBE per cubic meter of reactor per hour, a value comparable to other gasoline constituents. Such high performance could be sustained for at least 4--6 weeks. After the acclimation phase, the MTBE degrading biotrickling filters were characterized by their almost full conversion of MTBE to carbon dioxide and the absence of any degradation byproducts in either the gas or the liquid phase. They also exhibited a very high specific degradation activity per amount of biomass, and a low rate of biomass accumulation. An observed biomass yield of 0.1 g g{sup {minus}1} and a specific growth rate of 0.025 day{sup {minus}1} were determined for the biotrickling filter process culture. Further data on MTBE mass transfer and on the dynamic behavior of the biotrickling filter are presented in part 2 of this paper. Overall, the results demonstrate that MTBE can be effectively biodegraded under carefully controlled environmental conditions.

Fortin, N.Y.; Deshusses, M.A. [Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering] [Univ. of California, Riverside, CA (United States). Dept. of Chemical and Environmental Engineering

1999-09-01T23:59:59.000Z

30

Effect of Ethanol and Methyl-tert-Butyl Ether on Monoaromatic Hydrocarbon Biodegradation: Response Variability for Different Aquifer Materials Under Various Electron-Accepting Conditions  

SciTech Connect (OSTI)

Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic hydrocarbon degradation under different electron-accepting conditions commonly found in contaminated sites experiencing natural attenuation. Response variability was investigated by using aquifer material from four sites with different exposure history. The lag phase prior to BTEX (benzene, toluene, ethylbenzene, and xylenes) and ethanol degradation was typically shorter in microcosms with previously contaminated aquifer material, although previous exposure did not always result in high degradation activity. Toluene was degraded in all aquifer materials and generally under a broader range of electron-accepting conditions compared to benzene, which was degraded only under aerobic conditions. MtBE was not degraded within 100 days under any condition, and it did not affect BTEX or ethanol degradation patterns. Ethanol was often degraded before BTEX compounds, and had a variable effect on BTEX degradation as a function of electron-accepting conditions and aquifer material source. An occasional enhancement of toluene degradation by ethanol occurred in denitrifying microcosms with unlimited nitrate; this may be attributable to the fortuitous growth of toluene-degrading bacteria during ethanol degradation. Nevertheless, experiments with flow-through aquifer columns showed that this beneficial effect could be eclipsed by an ethanol-driven depletion of electron acceptors, which significantly inhibited BTEX degradation and is probably the most important mechanism by which ethanol could hinder BTEX natural attenuation. A decrease in natural attenuation could increase the likelihood that BTEX compounds reach a receptor as well as the potential duration of exposure.

Ruiz-Aguilar, G L; Fernandez-Sanchez, J M; Kane, S R; Kim, D; Alvarez, P J

2003-10-06T23:59:59.000Z

31

Sonolytic destruction of methyl tert-butyl ether by ultrasonic irradiation: The role of O{sub 3}, H{sub 2}O{sub 2}, frequency, and power density  

SciTech Connect (OSTI)

The kinetics of degradation of methyl tert-butyl ether (MTBE) by ultrasonic irradiation in the presence of ozone as functions of applied frequencies and applied power are investigated. Experiments are performed over the frequency range of 205--1,078 kHz. The higher overall reaction rates are observed at 358 and 618 kHz and then at 205 and 1,078 kHz. The observed pseudo-first-order rate constant, k{sub 0}, for MTBE degradation increases with increasing power density up to 250 W L{sup {minus}1}. A linear dependence of the first-order rate constant, k{sub O{sub 3}}, for the simultaneous degradation of O{sub 3} on power density is also observed. Naturally occurring organic matter (NOM) is shown to have a negligible effect on observed reaction rates.

Kang, J.W.; Hung, H.M.; Lin, A.; Hoffmann, M.R. [California Inst. of Tech., Pasadena, CA (United States). W.M. Keck Labs.] [California Inst. of Tech., Pasadena, CA (United States). W.M. Keck Labs.

1999-09-15T23:59:59.000Z

32

alkyl-tert alkyl ethers: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

TREAT METHYL- TERT-BUTYL ETHER CONTAMINATED CiteSeer Summary: Methyl-tert-butyl ether (MTBE) is a commonly used gasoline additive. Leaking underground storage tank systems,...

33

{gamma}-aminobutyric acid{sub A} (GABA{sub A}) receptor regulates ERK1/2 phosphorylation in rat hippocampus in high doses of Methyl Tert-Butyl Ether (MTBE)-induced impairment of spatial memory  

SciTech Connect (OSTI)

Experimental and occupational exposure to Methyl Tert-Butyl Ether (MTBE) has been reported to induce neurotoxicological and neurobehavioral effects, such as headache, nausea, dizziness, and disorientation, etc. However, the molecular mechanisms involved in MTBE-induced neurotoxicity are still not well understood. In the present study, we investigated the effects of MTBE on spatial memory and the expression and function of GABA{sub A} receptor in the hippocampus. Our results demonstrated that intraventricular injection of MTBE impaired the performance of the rats in a Morris water maze task, and significantly increased the expression of GABA{sub A} receptor {alpha}1 subunit in the hippocampus. The phosphorylation of ERK1/2 decreased after the MTBE injection. Furthermore, the decreased ability of learning and the reduction of phosphorylated ERK1/2 level of the MTBE-treated rats was partly reversed by bicuculline injected 30 min before the training. These results suggested that MTBE exposure could result in impaired spatial memory. GABA{sub A} receptor may play an important role in the MTBE-induced impairment of learning and memory by regulating the phosphorylation of ERK in the hippocampus.

Zheng Gang; Zhang Wenbin [Department of Occupational and Environmental Health, School of Public Health and Military Preventive Medicine, Fourth Military Medical University, Xi'an 710032 (China); Zhang Yun [465 Hospital, Jilin Medical College, Jilin 132001 (China); Chen Yaoming; Liu Mingchao; Yao Ting; Yang Yanxia; Zhao Fang [Department of Occupational and Environmental Health, School of Public Health and Military Preventive Medicine, Fourth Military Medical University, Xi'an 710032 (China); Li Jingxia; Huang Chuanshu [Nelson Institute of Environmental Medicine, New York University School of Medicine, Tuxedo, New York 10987 (United States); Luo Wenjing [Department of Occupational and Environmental Health, School of Public Health and Military Preventive Medicine, Fourth Military Medical University, Xi'an 710032 (China)], E-mail: luowenj@fmmu.edu.cn; Chen Jingyuan [Department of Occupational and Environmental Health, School of Public Health and Military Preventive Medicine, Fourth Military Medical University, Xi'an 710032 (China)], E-mail: jy_chen@fmmu.edu.cn

2009-04-15T23:59:59.000Z

34

E-Print Network 3.0 - anhydride-vinyl methyl ether Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

4-Methyl-2-pentanol Other secondary alcohols... - quire handling with precautions. Acrolein tert-Butyl methyl ether Di(1-propynl) ether n... Methoxy-1,3,5,7- cyclooctatetraene...

35

Aerobic mineralization of MTBE and tert-butyl alcohol by stream-bed sediment microorganisms  

SciTech Connect (OSTI)

Microorganisms indigenous to the stream-bed sediments at two gasoline-contaminated groundwater sites demonstrated significant mineralization of the fuel oxygenates, methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Up to 73% of [U-{sup 14}C]-MTBE and 84% of [U-{sup 14}C]-TBA were degraded to {sup 14}CO{sub 2} under mixed aerobic/anaerobic conditions. No significant mineralization was observed under strictly anaerobic conditions. The results indicate that, under the mixed aerobic/anaerobic conditions characteristic of stream-bed sediments, microbial processes may provide a significant environmental sink for MTBE and TBA delivered to surface water bodies by contaminated groundwater or by other sources.

Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H. [Geological Survey, Columbia, SC (United States)] [Geological Survey, Columbia, SC (United States)

1999-06-01T23:59:59.000Z

36

Production of methyl tert-alkyl ethers  

SciTech Connect (OSTI)

The transition to the use of unleaded gasolines has required the replacement of tetraethyl lead by oxygen-containing compounds such as methanol, ethanol, and ethers, which are termed {open_quotes}oxygenates{close_quotes} in the technical literature. These may be used in commercial gasolines in amounts of 10-15% by volume, equivalent to 2% oxygen by weight. When methyl tert-butyl ether (MTBE) is used, the oxygen content may amount to 2.7% by weight. This oxygenate gives a significant improvement of knock resistance of naphtha fractions, the greatest effects being observed for straight-run naphthas and reformer naphthas produced under normal conditions; the MTBE also improves the engine power and economy characteristics and lowers the carbon monoxide content in the exhaust by 15-30% and the hydrocarbon content by 7-8%. This paper describes methods for the production of MTBE and also methyl tert-alkyl ethers.

Trofimov, V.A.

1995-01-01T23:59:59.000Z

37

Treatment of Methyl tert-Butyl Ether Vapors in Biotrickling Filters. 1.  

E-Print Network [OSTI]

because of its low cost and blending characteristics. Depending on the season, reformulated gasoline of reactor per hour, a value comparable to other gasoline constituents. Such high performance could enhancer in gasoline. The use of MTBE increased rapidly after the 1990 Clean Air Act Amendments required

38

Impacts of Ethanol on Anaerobic Production of Tert-Butyl Alcohol (TBA) from Methyl Tert-Butyl Ether (MTBE) in Groundwater  

E-Print Network [OSTI]

Project title: Impacts of Ethanol on Anaerobic Production oftert-butanol (TBA). As ethanol is being promoted as ainvestigate the effect of ethanol release on existing MTBE

Scow, K M; MacKay, Douglas

2008-01-01T23:59:59.000Z

39

Whole-Genome Analysis of Methyl tert-Butyl Ether-Degrading Beta-Proteobacterium Methylibium petroleiphilum PM1  

E-Print Network [OSTI]

D. J. Slomczynski. 2003. BTEX/MTBE bioremediation: BionetsScow, and L. Alvarez-Cohen. MTBE and benzene biodegradationinteractions in BTEX and MTBE mixtures by an MTBE-degrading

2007-01-01T23:59:59.000Z

40

RELATIONS BETWEEN THE DETECTION OF METHYL TERT-BUTYL ETHER (MTBE) IN SURFACE AND GROUND WATER AND ITS CONTENT IN GASOLINE  

E-Print Network [OSTI]

AND ITS CONTENT IN GASOLINE By Michael J. Moran, Mike J. Halde, Rick M. Clawges and John S. Zogorski U in the United States as an octane enhancer and oxygenate in gasoline. Octane enhancement began in the late 1970's with the phase-out of tetraethyl lead from gasoline. The use of oxygenates was expanded

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

he U.S. Geological Survey's (USGS) National Water-Quality Assess-  

E-Print Network [OSTI]

of the wells included methyl tert-butyl ether (MTBE), tetrachloroethene (PCE), dichlorodifluoromethane, 1

42

Radiation chemistry of alternative fuel oxygenates -- Substituted ethers  

SciTech Connect (OSTI)

The electron beam process, an advanced oxidation and reduction technology, is based in the field of radiation chemistry. Fundamental to the development of treatment processes is an understanding of the underlying chemistry. The authors have previously evaluated the bimolecular rate constants for the reactions of methyl tert-butyl ether (MTBE) and with this study have extended their studies to include ethyl tert-butyl ether (ETBE), di-isopropyl ether (DIPE) and tert-amyl methyl ether (TAME) with the hydroxyl radical, hydrogen atom and solvated electron using pulse radiolysis. For all of the oxygenates the reaction with the hydroxyl radical appears to be of primary interest in the destruction of the compounds in water. The rates with the solvated electron are limiting values as the rates appear to be relatively low. The hydrogen atom rate constants are relatively low, coupled with the low yield in radiolysis, they concluded that these are of little significance in the destruction of the alternative fuel oxygenates (and MTBE).

Mezyk, S. P.; Cooper, W. J.; Bartels, D. M.; Tobien, T.; O'Shea, K. E.

1999-11-15T23:59:59.000Z

43

Experimental Pathology Laboratories, Inc. Methyl-Tertiary-Butyl Ether  

E-Print Network [OSTI]

COORDINATOR'S REPORT FOR LIFETIME CARCINOGENICITY STUDY OF METHYL-TERTIARY-BUTYL ETHER (MTBE) IN SPRAGUE CARCINOGENICITY STUDY OF METHYL-TERTIARY-BUTYL ETHER (MTBE) IN SPRAGUE-DAWLEY RATS CONDUCTED AT THE CANCER

Baker, Chris I.

44

Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2  

E-Print Network [OSTI]

K. : Atmospheric chemistry of gasoline-related emissions:chemistry. Methyl tert-butyl ether is a solvent and gasoline

2010-01-01T23:59:59.000Z

45

Kinetics and mechanism of the thermal dissociation of O,O'-bis(1,3,5-TRI-tert-butyl-4-oxo-2,5-cyclo-hexadienyl)-p-benzoquinone dioxime in solution  

SciTech Connect (OSTI)

The kinetics and mechanism of the thermal dissociation of O,O'-bis(1,3,5-tri-tert-butyl-4-oxo-2,5-cyclohexadienyl)-p-benzoquinone dioxime (quinol ether) in solutions in nonpolar solvents were investigated. The dissociation of the quinol ether is reversible two-stage process and involves the formation of an intermediate radical. In relation to the reaction conditions (initial concentration, temperature) the dissociation rate of the quinol ether obeys the kinetic equations omega = k/sub eff/ x c/sup 1/2/ or omega = k/sub 1/c. The change in the reaction order is due to the ratio of the rates of dissociation of the intermediate radical and of its reaction with the phenoxyl radical. The ESR spectra were recorded on a Varian E-9 radiospectrometer with high-frequency modulation of 100 kHz.

Khizhnyi, V.A.; Danilova, T.A.; Goloverda, G.Z.; Dobronravova, Z.A.

1987-09-20T23:59:59.000Z

46

antioxidant butylated hydroxytoluene: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

by Fusarium solani CiteSeer Summary: Fusarium solani degraded methyl tert-butyl ether (MTBE) and other oxygenated compounds from gasoline including tert-butyl alcohol (TBA). The...

47

Photoionization of methyl t-butyl ether (MTBE) and t-octyl methyl ether (TOME) and analysis of their pyrolyses by  

E-Print Network [OSTI]

Photoionization of methyl t-butyl ether (MTBE) and t-octyl methyl ether (TOME) and analysis 1999; accepted 20 July 1999 Abstract The pyrolysis products of neutral methyl-d3 t-butyl ether (MTBE-d3 from thermal cracking patterns. MTBE and TOME both exhibit base peaks at m/z 73 (which shifts to m/z 76

Morton, Thomas Hellman

48

Radical-anions of aromatic compounds. VII. Reaction of the products from the reduction of nitrobenzene by sodium with isopropyl and tert-butyl iodides  

SciTech Connect (OSTI)

The reaction of the products from the reduction of nitrobenzene by one and two equivalents of sodium with isopropyl iodide leads to the formation of N,O-diisopropylphenylhydroxylamine, while the reaction with tert-butyl iodide leads to p-(tert-butyl)nitrobenzene. Such a change in the nature of the reaction product in the transition from the primary and secondary alkyl halides to the tertiary alkyl halides clearly results from a change in the S/sub N/2 mechanism to the S/sub RN/1 mechanism, involving transfer of an electron from the radical-anion or dianion of nitrobenzene to the alkyl halide. The formation of considerable amounts of azoxybenzene in the reaction with tert-butyl iodide shows that the dianion and, to a lesser degree, the radical-anion of nitrobenzene exhibit basic characteristics.

Danilova, N.K.; Shteingarts, V.D.

1986-09-20T23:59:59.000Z

49

State Restrictions on Methyl Tertiary Butyl Ether (released in AEO2006)  

Reports and Publications (EIA)

By the end of 2005, 25 states had barred, or passed laws banning, any more than trace levels of methyl tertiary butyl ether (MTBE) in their gasoline supplies, and legislation to ban MTBE was pending in 4 others. Some state laws address only MTBE; others also address ethers such as ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME). Annual Energy Outlook 2006 assumes that all state MTBE bans prohibit the use of all ethers for gasoline blending.

2006-01-01T23:59:59.000Z

50

Water Quality  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

which can lead to public health problems. * MtBE (Methyl tert Butyl Ether), a gasoline additive, has begun to contaminate ground water supplies. * Similarly, perchlorate has...

51

Stratospheric ozone, global warming, and the principle of unintended consequences - an ongoing science and policy story  

E-Print Network [OSTI]

as methyl-tert-butyl ether (MTBE), lubricating oil and itsthe environment. Use of the MTBE additive in gasoline wasof gasoline laced with MTBE into groundwater resulted in

2013-01-01T23:59:59.000Z

52

Comparison of SPME headspace analysis to U.S. EPA method5030/8260B for MTBE monitoring  

SciTech Connect (OSTI)

A novel method for analysis of methyl tert-butyl ether andtert-butyl alcohol using solid phase microextraction is described andcompared to a standard method.

Stringfellow, William T.; Oh, Kuen-Chan

2005-02-01T23:59:59.000Z

53

Effects of water chemistry on NF/RO membrane structure and performance  

E-Print Network [OSTI]

methyl tert-butyl ether (MTBE), benzene, ethylbenzene,TCE** Industrial C 2 HCl 3 MTBE** [48] Industrial C 5 H 12 O

Mo, Yibing

2013-01-01T23:59:59.000Z

54

Cometabolic bioremediation  

E-Print Network [OSTI]

Intrinsic bioremediation of MTBE-contaminated groundwater atcontaminants, e.g. PCE, TCE, MTBE, TNT, dioxane, atrazine,Methyl tert-butyl ether (MTBE) has also been remediated

Hazen, Terry C.

2010-01-01T23:59:59.000Z

55

Atmospheric Methyl Tertiary Butyl Ether (MTBE) at a Rural Mountain Site in California  

E-Print Network [OSTI]

Atmospheric Methyl Tertiary Butyl Ether (MTBE) at a Rural Mountain Site in California Gunnar W. Schade,* Gabrielle B. Dreyfus, and Allen H. Goldstein ABSTRACT (CARB) measured MTBE in urban regions in 1995­ 1996, reporting a range of 0.4 to 13.2 ppbv in the LosMethyl tertiary butyl ether (MTBE

Cohen, Ronald C.

56

Pyrolysis of Organic Molecules Relevant to Combustion as Monitored by Photoionization Time-of-Flight Mass Spectrometry  

E-Print Network [OSTI]

is observed, which is similar to MTBE in this system whichisobutene formed from MTBE, is found to occur. REFERENCES [methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (

Weber, Kevin Howard

2010-01-01T23:59:59.000Z

57

Life-cycle Environmental Inventory of Passenger Transportation in the United States  

E-Print Network [OSTI]

Methyl tert?Butyl Ether (MTBE); http://www.atsdr.cdc.gov/Methyl Tertiary Butyl  Ether  (MTBE),  which  was  easily accounting was not performed on MTBE and the result  of 

Chester, Mikhail V

2008-01-01T23:59:59.000Z

58

Monitoring synaptic protein dynamics with higher temporal, spatial, and molecular resolution  

E-Print Network [OSTI]

Spectrometry mSOG MiniSOG MTBE Methyl tert-butyl ether mTORMethyl tert-butyl ether (MTBE, 1.4 mL) was then added for1,000 g, 5 min). The MTBE layer was collected into a 1.5-mL

Butko, Margaret

2012-01-01T23:59:59.000Z

59

he increasing frequency of detection of the widely used gasoline additive methyl tert-  

E-Print Network [OSTI]

T he increasing frequency of detection of the widely used gasoline additive methyl tert- butyl, the September 15, 1999, Report of the Blue Ribbon Panel on Oxygenates in Gasoline (1) states that between 5 with large releases (e.g., LUFTs). Unprecedented growth in use Use of MTBE as a gasoline additive began

60

QUANTIFYING NON-POINT SOURCES OF VOLATILE ORGANIC COMPOUNDS IN STORMWATER FROM A PARKING LOT  

E-Print Network [OSTI]

-butyl ether (MTBE) on urban particles indicates a site- specific interaction between MTBE and a particulate is a possible source only for the gasoline oxygenate methyl tert-butyl ether (MTBE). Lopes and Bender (1998

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Fluctuating micro-heterogeneity in water–tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies  

SciTech Connect (OSTI)

Water–tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with x{sub TBA} ? 0.03–0.07. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at x{sub TBA} ? 0.05. We note that “islands” of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak nonlinearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, x{sub TBA} ? 0.45, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level.

Banerjee, Saikat; Furtado, Jonathan; Bagchi, Biman, E-mail: bbagchi@sscu.iisc.ernet.in [SSCU, Indian Institute of Science, Bangalore 560012 (India)] [SSCU, Indian Institute of Science, Bangalore 560012 (India)

2014-05-21T23:59:59.000Z

62

Low-temperature CVD of iron, cobalt, and nickel nitride thin films from bis[di(tert-butyl)amido]metal(II) precursors and ammonia  

SciTech Connect (OSTI)

Thin films of late transition metal nitrides (where the metal is iron, cobalt, or nickel) are grown by low-pressure metalorganic chemical vapor deposition from bis[di(tert-butyl)amido]metal(II) precursors and ammonia. These metal nitrides are known to have useful mechanical and magnetic properties, but there are few thin film growth techniques to produce them based on a single precursor family. The authors report the deposition of metal nitride thin films below 300?°C from three recently synthesized M[N(t-Bu){sub 2}]{sub 2} precursors, where M?=?Fe, Co, and Ni, with growth onset as low as room temperature. Metal-rich phases are obtained with constant nitrogen content from growth onset to 200?°C over a range of feedstock partial pressures. Carbon contamination in the films is minimal for iron and cobalt nitride, but similar to the nitrogen concentration for nickel nitride. X-ray photoelectron spectroscopy indicates that the incorporated nitrogen is present as metal nitride, even for films grown at the reaction onset temperature. Deposition rates of up to 18?nm/min are observed. The film morphologies, growth rates, and compositions are consistent with a gas-phase transamination reaction that produces precursor species with high sticking coefficients and low surface mobilities.

Cloud, Andrew N.; Abelson, John R., E-mail: abelson@illinois.edu [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 201 Materials Science and Engineering Building, 1304 W. Green St., Urbana, Illinois 61801 (United States); Davis, Luke M.; Girolami, Gregory S., E-mail: girolami@scs.illinois.edu [School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave., Urbana, Illinois 61801 (United States)

2014-03-15T23:59:59.000Z

63

Fluctuating micro-heterogeneity in water - tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies  

E-Print Network [OSTI]

Water - tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with $x_{\\text{TBA}} \\approx 0.03 - 0.07$. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at $x_{\\text{TBA}} \\approx 0.05$. We note that "islands" of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak non-linearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, $x_{\\text{TBA}} \\approx 0.45$, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level.

Saikat Banerjee; Jonathan Furtado; Biman Bagchi

2014-02-20T23:59:59.000Z

64

Measurements of volatile organic compounds at a suburban ground site (T1) in Mexico City during the MILAGRO 2006 campaign: measurement comparison, emission ratios, and source attribution  

E-Print Network [OSTI]

methyl tert-butyl ether (MTBE) at 57 amu has been previouslyby a fragment of MTBE (62%) with minor contributions fromFortner and Knighton, 2008). MTBE also in- terfered (16%)

2011-01-01T23:59:59.000Z

65

APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Aug. 2004, p. 47204726 Vol. 70, No. 8 0099-2240/04/$08.00 0 DOI: 10.1128/AEM.70.8.47204726.2004  

E-Print Network [OSTI]

contamination of surface and groundwater resources by the gasoline oxygenate methyl tert-butyl ether (MTBE) is leading to its phaseout. Ethanol, a likely candidate to substitute MTBE, is increasingly being used

Alvarez, Pedro J.

66

Assessing the Effectiveness of California's Underground Storage Tank Annual Inspection Rate Requirements  

E-Print Network [OSTI]

Methyl Tert-Butyl Ether (MTBE), a gasoline additive. Thefor the lion’s share of MTBE contamination, as well asIn response to the MTBE crisis, California increased the

Cutter, W. Bowman

2008-01-01T23:59:59.000Z

67

Trichloroethene Removal From Waste Gases in Anaerobic Biotrickling Filters Through Reductive Dechlorination  

E-Print Network [OSTI]

methyl tert-butyl ether (MTBE) vapors into water was used.MTBE is highly soluble in water (dimensionless Henry’sgas stream was laden with MTBE vapors (200-300 mg m -3 )

Popat, Sudeep Chandrakant

2010-01-01T23:59:59.000Z

68

Observation on the biodegradation and bioremediation potential of methyl t-butyl ether  

SciTech Connect (OSTI)

There have been few reports documenting evidence for the biodegradation of the fuel oxygenate alkyl ether, methyl t-butyl ether (MTBE) in groundwater, soils, and biosludges. Partial (or complete) microbial breakdown of MTBE has been observed in an anaerobic subsoil, a river sediment under methanogenic conditions, a cyclohexane-degrading bacterial consortium and a pure culture of the methylotroph, Methylisnus trichosporium OB3b. An aerobic bacterial enrichment (BC-1) isolated from an industrial transient (non-accumulating) metabolic intermediate. The studies suggest that MTBE is cleaved by BC-1 to TBA which is then metabolized via isopropanol and acetone. There is little information on the occurrence of indigenous MTBE-degraders in groundwater, soils and activated sludges. Preliminary evidence has been obtained, however, from a marketing terminal groundwater site that naturally-occurring MTBE-degraders are present in some monitoring wells. Microcosm experiments with groundwater from this aquifer show that MTBE is aerobically degraded (no TBA formed) with a first-order decay rate (0.31/day) similar to BTEX. Also, MTBE did not inhibit the intrinsic biodegradation potential of BTEX in groundwater microcosms. In summary, the data presented indicate that MTBE biodegradation has been observed in some environmental media. Further work is needed to assess the feasibility of using indigenous or derived aerobic and anaerobic MTBE-degrading cultures for treating fuel ethers in groundwaters or wastewater with in-situ or ex-situ bioremediation technologies.

Salanitro, J.; Wisniewski, H.; McAllister, P. [Shell Development Co., Houston, TX (United States)

1995-12-31T23:59:59.000Z

69

Treatment of methyl t-butyl ether contaminated water using a dense medium plasma reactor, a mechanistic and kinetic investigation  

E-Print Network [OSTI]

and oxidation mechanisms of methyl t-butyl ether (MTBE) in a dense medium plasma (DMP) reactor utilizing gas for the removal of MTBE from an aqueous solution in the DMP reactor. Rate constants are also derived for three reactor configurations and two pin array spin rates. The oxidation products from the treatment of MTBE

Dandy, David

70

Acute toxicity of methyl-tertiary-butyl ether (MTBE) to aquatic organisms  

SciTech Connect (OSTI)

Due to the recent amendment of the Clean Air Act, oxygenates are now being added to gasolines to boost octane and reduce air pollution from combustion in heavily populated areas. Oxygenates such as alcohols (i.e. methanol) and ethers (methyl-tertiary-butyl ether, MTBE) are commonly being used. A series of bioassay studies have been conducted with MTBE, one of the most commonly used octane-enhancing additives. Freshwater and marine studies were conducted with fish, invertebrates and algae to determine the impact of this material on the environment following accidental spills. Static-renewal studies were run to ensure maintenance of MTBE, a highly volatile material in the test containers. Chemical confirmation of exposure concentrations demonstrated the adequacy of the exposure system. Mysid shrimp were highly sensitive to MTBE, with significantly less effect observed with the other species evaluated. These data have implications for spill response, particularly since MTBE is slow to biodegrade and will rapidly move through groundwater. Comparative data for other oxygenates will also be discussed.

BenKinney, M.T.; Barbieri, J.F.; Gross, J.S.; Naro, P.A. [Stonybrook Labs. Inc., Princeton, NJ (United States)

1994-12-31T23:59:59.000Z

71

Isobaric vapor-liquid equilibria in the systems methyl 1,1-dimethylethyl ether + hexane and + heptane  

SciTech Connect (OSTI)

The vapor-liquid equilibrium at 94 kPa has been determined for the binary systems of methyl 1,1-dimethylethyl ether (MTBE) with hexane and with heptane. Both systems deviate slightly from ideal behavior, can be described as regular solutions, and do not present an azeotrope. The activity coefficients and boiling point of the solutions were correlated with its composition by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak-Tamir equations.

Wisniak, J.; Magen, E.; Shachar, M.; Zeroni, I.; Segura, H. [Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel). Dept. of Chemical Engineering] [Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel). Dept. of Chemical Engineering; Reich, R. [Univ. de Concepcion (Chile). Dept. of Chemical Engineering] [Univ. de Concepcion (Chile). Dept. of Chemical Engineering

1997-03-01T23:59:59.000Z

72

Toxicity of methyl tertiary butyl ether to Daphnia magna and photobacterium phosphoreum  

SciTech Connect (OSTI)

Methyl tertiary butyl ether (MTBE) is a liquid organic compound added to gasoline to increase its oxygen content and to reduce the emission of carbon monoxide during combustion in many urban areas. In order to meet the 1990 Clean Air Act amendments, gasoline must contain 2.7% oxygen (by weight) or 15% (by volume) of MTBE in gasoline to meet the regulations for the control of carbon monoxide emissions. Health effects caused by inhalation of MTBE include headaches, dizziness, irritated eyes and nausea; MTBE is one of cancer--causing chemicals. Intracaval injection of MTBE (0.2 mg/kg) caused the highest mortality (100%) in rats. General anesthetic effect induced by MTBE was found at or above 1200 mg/kg body weight; Rosenkranz and Klopman (1991) predicted that MTBE is neither a genotoxicant nor a carcinogen. Nevertheless, the safety of using MTBE in oxygenated fuels is now being questioned from its potential as groundwater pollutant. This study measures the toxicity of MTBE to Daphnia magna and Photobacterium phosphoreum. 13 refs.

Gupta, G.; Lin, Y.J. [Univ. of Maryland Eastern Shore, Princess Anne, MD (United States)

1995-10-01T23:59:59.000Z

73

Disposition, metabolism, and toxicity of methyl tertiary butyl ether, an oxygenate for reformulated gasoline  

SciTech Connect (OSTI)

Studies of the toxicology of methyl tertiary butyl ether (MTBE) were reviewed as a possible information base for evaluating the health effects of evaporative emissions from reformulated gasoline (RFG). Perirenal fat/blood MTBE concentration ratios ranged from 9.7 to 11.6 after 15 wk of intermittent exposure. During an oxyfuels program in Fairbanks, AK, blood levels of occupationally exposed workers were 0.2-31.5 {mu}g/L MTBE and 1.6 to 72.2 {mu}g/L TBA with a mean TBA:MTBE blood concentration ratio of 4.2. In patients who received MTBE by percutaneous, transhepatic puncture for the dissolution of cholesterol gallstones, concentrations of MTBE in fat tissue reached 60 and 300 {mu}g/g at a treatment time when mean blood MTBE was less than 20 {mu}g/ml. The results of laboratory and clinical studies indicate that metabolites of MTBE may contribute to the nephropathy, neoplasms, and other pathological changes associated with repeated exposure to MTBE in experimental animals. It is concluded that such studies can provide a well-defined database for quantitatitive safety comparisons and health risk-benefit analyses of MTBE and other oxygenates in RFG. 39 refs., 1 tab.

Hutcheon, D.E.; Hove, W. ten; Boyle, J. III [UMDNJ, New Jersey Medical Schook, Newark, NJ (United States)] [UMDNJ, New Jersey Medical Schook, Newark, NJ (United States); Arnold, J.D. [Arnold & Arnold, Inc., Kansas City, MO (United States)] [Arnold & Arnold, Inc., Kansas City, MO (United States)

1996-04-05T23:59:59.000Z

74

International Journal of Mass Spectrometry 249250 (2006) 303310 Pyrolysis of 2-methoxy-2,3,3-trimethylbutane (MTMB) monitored by  

E-Print Network [OSTI]

used fuel oxygenates MTBE and TAME), the predominance of bond homolysis at temperatures >900 K suggests homologues ­ methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (TAME) ­ present a new set of problems discussed as alternatives to MTBE and TAME, because they are expected to be much less soluble in water. More

Morton, Thomas Hellman

75

Effect of thermal history on the molecular orientation in polystyrene/poly(vinyl methyl ether) blends  

E-Print Network [OSTI]

ether) (PS/PVME) has been studied using polarization modulation infrared linear dichroism (PM to an increased orientation if the heating time at 51 8C is kept short. Moreover, PS and PVME develop a larger) blends; Thermal history; Polarization modulation infrared linear dichroism 1. Introduction The influence

Pezolet, Michel

76

Alveolar breath sampling and analysis to assess exposures to methyl tertiary butyl ether (MTBE) during motor vehicle refueling  

SciTech Connect (OSTI)

In this study we present a sampling and analytical methodology that can be used to assess consumers` exposures to methyl tertiary butyl ether (MTBE) that may result from routine vehicle refueling operations. The method is based on the collection of alveolar breath samples using evacuated one-liter stainless steel canisters and analysis using a gas chromatograph-mass spectrometer equipped with a patented `valveless` cryogenic preconcentrator. To demonstrate the utility of this approach, a series of breath samples was collected from two individuals (the person pumping the fuel and a nearby observer) immediately before and for 64 min after a vehicle was refueled with premium grade gasoline. Results demonstrate low levels of MTBE in both subjects` breaths before refueling, and levels that increased by a factor of 35 to 100 after the exposure. Breath elimination models fitted to the post exposure measurements indicate that the half-life of MTBE in the first physiological compartment was between 1.3 and 2.9 min. Analysis of the resulting models suggests that breath elimination of MTBE during the 64 min monitoring period was approximately 155 {mu}g for the refueling subject while it was only 30 {mu}g for the nearby observer. This analysis also shows that the post exposure breath elimination of other gasoline constituents was consistent with previously published observations. 20 refs., 3 figs., 4 tabs.

Lindstrom, A.B.; Pleil, J.D. [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States)

1996-07-01T23:59:59.000Z

77

Race to license new MTBE and TAME routes heats up  

SciTech Connect (OSTI)

With refineries and petrochemical manufacturers continuing to gear up production of oxygenates for use in reformulated fuels, new routes to methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (TAME) are clearly hot items in the licensing market. And probably nowhere has the competition become as intense as in offerings for skeletal isomerization technologies to boost ethers production from fluid catalytic cracking and steam cracking.

Rotman, D.

1993-01-06T23:59:59.000Z

78

PROOF COPY [023113] 008209QEE [023113]008209QEE  

E-Print Network [OSTI]

as a replacement for the gasoline oxygenate, methyl tert-butyl ether MTBE , may lead to indirect impacts related facilitate the migration of pre-existing contamination. MTBE 25 mg/L influent was not degraded inlet by one order of magnitude relative to columns fed BTEX alone or with MTBE. However, 16S

Alvarez, Pedro J.

79

Environmental Toxicology and Chemistry, Vol. 21, No. 12, pp. 26312639, 2002 Printed in the USA  

E-Print Network [OSTI]

--Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic compared to benzene, which was degraded only under aerobic conditions. The MtBE was not degraded within 100 to phase out MtBE as a gasoline oxy- genate is likely to significantly increase the use of ethanol

Alvarez, Pedro J.

80

90% of new cars have engines specially designed to run on hydrous ethanol. This avoids the expense of remov-  

E-Print Network [OSTI]

competes with gasoline (petrol), diesel and MTBE (methyl tert-butyl ether, added to gasoline to MTBE, however, ethanol is comparable regarding price per energy unit and has considerable environmental advantages. MTBE is added to gasoline as an octane booster, replac- ing the lead formerly used

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Physico-chemical and biological characterization of an aquifer polluted with Yves Benoit (1)  

E-Print Network [OSTI]

to in order to meet specific requirements. Oxygenates such as methyl tert-butyl ether (MTBE) or ethyl tert on groundwater was not estimated prior to their utilization and the actual level of MTBE and ETBE contamination of MTBE- and ETBE-biodegradation is quite poor. Two directives have been adopted in the EU to promote

Paris-Sud XI, Université de

82

Critical Reviews in Environmental Science and Technology, 00(0):000000 (2001) 1064-3389/01/$.50  

E-Print Network [OSTI]

water contamination by methyl tert-butyl ether (MTBE) have made policymakers more cognizant of the need reformulated gasoline (RFG) (2% oxygen) year-round to reduce emissions that contribute to ozone formation. MTBE-making process that lead to the widespread use of MTBE over the last decade is now quite controversial (BRP, 1999

Alvarez, Pedro J.

83

Author's personal copy Automobile proximity and indoor residential concentrations of BTEX and MTBE  

E-Print Network [OSTI]

Author's personal copy Automobile proximity and indoor residential concentrations of BTEX and MTBE to indoor benzene and MTBE concentrations appeared to have been dominated by car exhaust concentrations of other BTEX components and methyl tert-butyl ether (MTBE) have been reported [5,6]. Up until

Siegel, Jeffrey

84

Biotreatment of groundwater contaminated with MTBE: interaction of common environmental co-contaminants  

E-Print Network [OSTI]

Biotreatment of groundwater contaminated with MTBE: interaction of common environmental co November 2005 Key words: aerobic, biodegradation, BTEX, co-contaminant, MTBE, TBA Abstract Contamination of groundwater with the gasoline additive methyl tert-butyl ether (MTBE) is often accompanied by many aromatic

85

Canada could get three MTBE plants  

SciTech Connect (OSTI)

This article reports on the proposed development of three methyl tert-butyl ether (MTBE) plants in Canada. MTBE is used as an oxygenated fuel additive. The author discusses how demand for MTBE is increasing due to the regulation of leaded gasoline by the U.S. and Canadian governments. The exportation of MTBE from Canada to the U.S. is highlighted.

Anderson, E

1990-03-01T23:59:59.000Z

86

MTBE still facing pressure from ethanol under latest fuel proposal  

SciTech Connect (OSTI)

The US EPA's finalized reformulated gasoline rule, part of Phase II of the 1990 Clean Air Act, signals a possible turnaround for the sluggish methyl tert-butyl ether (MTBE) market. But if a 30% renewable fuels proposal favoring ethanol passes, pressure could continue for MTBE.

Lucas, A.

1994-01-26T23:59:59.000Z

87

Water Research Institute Annual Technical Report  

E-Print Network [OSTI]

Air Act mandated oxygenated gasoline containing methyl tert-butyl ether (MtBE) in certain areas percent. The State of Maine elected to use reformulated gasoline (RFG) that contained at least 11 percent and by 1995, oxygenated gasoline use was common in the northeast. Soon after the widespread use of gasoline

88

Biomass burning and urban air pollution over the Central Mexican Plateau  

E-Print Network [OSTI]

the urban tracers (e.g. C 2 H 2 , MTBE, toluene) are highlymethyl tert-butyl ether (MTBE) because their shorter atmo-

2009-01-01T23:59:59.000Z

89

First Annual U.S. Department of Energy Office of Science Joint Genome Institute User Meeting  

E-Print Network [OSTI]

Genome Analysis of MTBE-Degrading Beta- Proteobacteriummethyl tert- butyl ether (MTBE). Strain PM1 can alsooften co-contaminants with MTBE in groundwater, including

Various

2006-01-01T23:59:59.000Z

90

Saudi MTBE project revived  

SciTech Connect (OSTI)

Alujain Corp., a member of the Xenel group of Saudi Arabia, is going ahead with plans to build an 800,000-m.t./year methyl tert-butyl ether (MTBE) plant. Bechtel has been appointed project manager for the plant, which will be owned by a new company, National Fuel Additives (Tahseen). Bechtel will help evaluate proposals already submitted for the lump sum turnkey job.

NONE

1996-01-17T23:59:59.000Z

91

MTBE from butadiene-rich C/sub 4/s  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE), is made by reacting methanol with isobutylene. The preferred source of isobutylene is a steam cracker C/sub 4/ cut from which butadiene has been removed. However, moving the MTBE synthesis upstream of the butadiene extraction will improve the extraction step. The following is a review of conditions imposed on the MTBE unit's design and operation when placed in this new location.

Ancillotti, F.; Pescarollo, E.; Szatmari, E.; Lazar, L.

1987-12-01T23:59:59.000Z

92

Synthesis of octane enhancer during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 4, July 1, 1991--September 30, 1991  

SciTech Connect (OSTI)

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. Addition of methanol to slurry phase FT synthesis making iso-olefins.

Marcelin, G.

1991-12-15T23:59:59.000Z

93

Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 5, October 1, 1991--December 31, 1991  

SciTech Connect (OSTI)

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. Addition of methanol to slurry phase FT synthesis making iso-olefins.

Marcelin, G.

1992-06-10T23:59:59.000Z

94

Health studies indicate MTBE is safe gasoline additive  

SciTech Connect (OSTI)

Implementation of the oxygenated fuels program by EPA in 39 metropolitan areas, including Fairbanks and Anchorage, Alaska, in the winter of 1992, encountered some unexpected difficulties. Complaints of headaches, dizziness, nausea, and irritated eyes started in Fairbanks, jumped to Anchorage, and popped up in various locations in the lower 48 states. The suspected culprit behind these complaints was the main additive for oxygenation of gasoline is methyl tert-butyl ether (MTBE). A test program, hastily organized in response to these complaints, has indicated that MTBE is a safe gasoline additive. However, official certification of the safety of MTBE is still awaited.

Anderson, E.V.

1993-09-01T23:59:59.000Z

95

Veba in MTBE project, cutting aromatics  

SciTech Connect (OSTI)

The new owners of the refinery and petrochemical complex at Schwedt in eastern Germany-RWE-DEA (Hamburg), Veba Oel (Gelsenkirchen), Agip (Rome), Total (Paris), and Elf-Aquitaine (Paris)-plan to build a 60,000-m.t./year methyl tert-butyl ether (MTBE) plant at the site for 1994-1995 completion. The MTBE project forms part of the consortium`s announced DM1.5-billion ($500 million) investment program for the complex that aims to raise refinery throughput from 8 million m.t./year to 12 million m.t./year by 1994 and hike production of naphtha and benzene.

Young, I.; Roberts, M.

1992-04-15T23:59:59.000Z

96

MTBE growth limited despite lead phasedown in gasoline  

SciTech Connect (OSTI)

This month's legislated reduction of the allowable amount of lead additives in gasoline will increase demand strongly for methyl-tert-butyl ether (MTBE) as an octane enhancer, but the economics of the refinery business and the likelihood of rapidly increasing high-octane gasoline imports probably will limit the size of the business in coming years. MTBE will be used to fill the octane gap now, but economics and imports of gasoline later on could hold down demand. The limited growth in sales of MTBE is discussed.

Storck, W.

1985-07-15T23:59:59.000Z

97

MTBE: Capacity boosts on hold amid demand concerns  

SciTech Connect (OSTI)

Uncertainty reigns in the methyl tert-butyl ether (MTBE) market. {open_quotes}We have no choice but to put our expansion plans on the back burner,{close_quotes} says one producer. {open_quotes}Because of government actions, there are no MTBE plants being built or expanded.{close_quotes} Spot MTBE prices have risen ti 82 cts- 83 cts/gal from 76 cts-78 cts/gal earlier this month as the demand for octane enhancement increases for the summer driving season. Some observers say EPA may relax different oxygen requirements for gasoline in different seasons. That would simplify production and supply for MTBE makers.

NONE

1995-05-03T23:59:59.000Z

98

Methanex considers methanol, MTBE in Qatar  

SciTech Connect (OSTI)

CW has learned that Methanex Corp. is considering entering one of two methanol and methyl tert-butyl ether (MTBE) projects in Qatar. Executive v.p. Michael Wilson says that part of the company`s New Zealand plant could be moved to a site in Qatar, which would lower capital costs for the possible project by $75 million-$100 million. Both Qatar General Petroleum Corp. and Qatar Fuel Additives are developing methanol and MTBE projects at Umm Said, Qatar. Methanex says its goal is to ensure low-cost feedstocks.

NONE

1995-12-13T23:59:59.000Z

99

Total to withdraw from Qatar methanol - MTBE?  

SciTech Connect (OSTI)

Total is rumored to be withdrawing from the $700-million methanol and methyl tert-butyl ether (MTBE) Qatar Fuel Additives Co., (Qafac) project. The French company has a 12.5% stake in the project. Similar equity is held by three other foreign investors: Canada`s International Octane, Taiwan`s Chinese Petroleum Corp., and Lee Change Yung Chemical Industrial Corp. Total is said to want Qafac to concentrate on methanol only. The project involves plant unit sizes of 610,000 m.t./year of MTBE and 825,000 m.t./year of methanol. Total declines to comment.

NONE

1996-05-01T23:59:59.000Z

100

Health concerns fuel EPA study of ETBE and TAME  

SciTech Connect (OSTI)

Citing possible health risks associated with the use of methyl tert-butyl ether (MTBE) in winter-blend gasoline and requirements of the 1990 Clean Air Act (CAA), EPA has called for testing the health effects of ethyl tert-butyl ether (EBTE) and tert-amyl methyl ether (TAME). The program calls for toxicity testing to develop data on the health effects of ETBE and TAME. EPA may require chemical manufacturers and processors to provide the data. A public meeting will be held this week to begin working on an agreement. EPA says most of the data should be collected in 1995 and expects the program to cost approximately $3 million. In December, EPA floated a proposal to require 30% of the oxygenates used in the reformulated gasoline program to come from renewable sources such as ETBE and ethanol. Although EPA found no serious health risks associated with MTBE, questions remain, which is why EPA says it will test the use of ETBE and TAME. William Piel, business manager for oxygenated fuels at Arco Chemical (Newtown Square, PA), says testing is {open_quotes}just a formality.{close_quotes} There should be no difference in results among MTBE, ETBE, or TAME, he says. But ETBE and TAME have much lower volatility than MTBE, which would mean significantly less exposure to these oxygenates, Piel says. Arco is the biggest producer of MTBE but also has capability to make ETBE.

Lucas, A.

1994-05-11T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

High octane ethers from synthesis gas-derived alcohols  

SciTech Connect (OSTI)

The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H[sub 2]/CO/CO[sub 2] coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-l-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The last stage of the synthesis involves direct coupling of synthesis gas-derived methanol and isobutanol that has been demonstrated by us to occur over superacid catalysts to yield methyl isobutyl ether (MIBE) at moderate pressures and a mixture of methanol and isobutene at low pressures. MIBE is an isomer of MTBE and a process is proposed whereby MTBE from the two alcohols is maximized and MIBE is minimized. This will be achieved by the proper choice of reaction conditions, i.e. intermediate pressures, and of inorganic acid catalysts that are stable at temperatures higher than 200[degree]C, at which the carbonium ion reaction coupling of the two alcohols to MTBE is more effective than the oxonium ion or ester reaction coupling to MIBE. Both organic and inorganic catalysts will be investigated, and the better catalysts of these classes will be subjected to long term performance studies. The long term performance studies of the combined process will extend to 1000 hr and detailed analytical data for all products will be provided.

Klier, K.; Herman, R.G.; Feeley, O.C.; Johansson, M.A.

1992-07-01T23:59:59.000Z

102

Oxidative desulfurization of dibenzothiophene with tert-butyl hydro peroxide in a photochemical micro-reactor.  

E-Print Network [OSTI]

??Sulfur content in fuels is an increasingly critical environmental issue. Hydrodesulfurization removes sulfur from hydrocarbons; however, further desulfurization is necessary in fuels. New methods are… (more)

Hebert, Eilleen M.

2007-01-01T23:59:59.000Z

103

Thermal and Photochemistry of tert-Butyl Iodide on Rutile TiO(110). | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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104

NIOSH Manual of Analytical Methods (third edition). Fourth supplement  

SciTech Connect (OSTI)

The NIOSH Manual of Analytical Methods, 3rd edition, was updated for the following chemicals: allyl-glycidyl-ether, 2-aminopyridine, aspartame, bromine, chlorine, n-butylamine, n-butyl-glycidyl-ether, carbon-dioxide, carbon-monoxide, chlorinated-camphene, chloroacetaldehyde, p-chlorophenol, crotonaldehyde, 1,1-dimethylhydrazine, dinitro-o-cresol, ethyl-acetate, ethyl-formate, ethylenimine, sodium-fluoride, hydrogen-fluoride, cryolite, sodium-hexafluoroaluminate, formic-acid, hexachlorobutadiene, hydrogen-cyanide, hydrogen-sulfide, isopropyl-acetate, isopropyl-ether, isopropyl-glycidyl-ether, lead, lead-oxide, maleic-anhydride, methyl-acetate, methyl-acrylate, methyl-tert-butyl ether, methyl-cellosolve-acetate, methylcyclohexanol, 4,4'-methylenedianiline, monomethylaniline, monomethylhydrazine, nitric-oxide, p-nitroaniline, phenyl-ether, phenyl-ether-biphenyl mixture, phenyl-glycidyl-ether, phenylhydrazine, phosphine, ronnel, sulfuryl-fluoride, talc, tributyl-phosphate, 1,1,2-trichloro-1,2,2-trifluoroethane, trimellitic-anhydride, triorthocresyl-phosphate, triphenyl-phosphate, and vinyl-acetate.

Not Available

1990-08-15T23:59:59.000Z

105

Arco chimie focuses on PA at FOS  

SciTech Connect (OSTI)

Arco Chimie France (Fos-sur-Mer), at a recent meeting at its southern France manufacturing site, emphasized that future strategy is strongly focused on its propylene oxide (PO) and derivatives activities. The F2.5 billion ($466 million)-Fe billion/year operation manufactures 200,000 m.t./year of PO, about 70% for captive use and the balance for the merchant market; 550,000 m.t./year of methyl tert butyl ether (MTBE); 97,000 m.t./year of polyols; and 70,000 m.t./year of propylene glycols. There has been talk of Arco modifying its Fos MTBE plant to make it flexible for ethyl tert-butyl ether (ETBE) output; the parent company already operates an MTBE/ETBE pilot unit at Corpus Christi, TX. But Arco Chimie notes there is insufficient bioethanol feedstock availability to convert all production to ETBE. The company would also require investment in new storage capacity for ethanol and ETBE. However, France's biofuels program is not yet clearly defined, and it is politically sensitive because it depends heavily on government subsidies offered to farmers. That, says Arco, makes it impossible to have an accurate idea of how much ethanol will be available.

Jackson, D.

1992-12-02T23:59:59.000Z

106

Thermodynamics of Hydrogen Production from Dimethyl Ether Steam Reforming and Hydrolysis  

SciTech Connect (OSTI)

The thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the process of dimethyl ether (DME) steam reforming were investigated as a function of steam-to-carbon ratio (0-4), temperature (100 C-600 C), pressure (1-5 atm), and product species: acetylene, ethanol, methanol, ethylene, methyl-ethyl ether, formaldehyde, formic acid, acetone, n-propanol, ethane and isopropyl alcohol. Results of the thermodynamic processing of dimethyl ether with steam indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 C and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure was observed to shift the equilibrium toward the reactants; increasing the pressure from 1 atm to 5 atm decreased the conversion of dimethyl ether from 99.5% to 76.2%. The order of thermodynamically stable products in decreasing mole fraction was methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol, methyl-ethyl ether and methanol--formaldehyde, formic acid, and acetylene were not observed. The optimal processing conditions for dimethyl ether steam reforming occurred at a steam-to-carbon ratio of 1.5, a pressure of 1 atm, and a temperature of 200 C. Modeling the thermodynamics of dimethyl ether hydrolysis (with methanol as the only product considered), the equilibrium conversion of dimethyl ether is limited. The equilibrium conversion was observed to increase with temperature and steam-to-carbon ratio, resulting in a maximum dimethyl ether conversion of approximately 68% at a steam-to-carbon ratio of 4.5 and a processing temperature of 600 C. Thermodynamically, dimethyl ether processed with steam can produce hydrogen-rich fuel-cell feeds--with hydrogen concentrations exceeding 70%. This substantiates dimethyl ether as a viable source of hydrogen for PEM fuel cells.

T.A. Semelsberger

2004-10-01T23:59:59.000Z

107

Propenyl ether monomers for photopolymerization  

DOE Patents [OSTI]

Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of the above formula together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

Crivello, J.V.

1996-10-22T23:59:59.000Z

108

CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS  

SciTech Connect (OSTI)

A novel 1,2-ethanediol, bis(hydrogen sulfate), disodium salt precursor-based solid acid catalyst with a zirconia substrate was synthesized and demonstrated to have significantly enhanced activity and high selectivity in producing methyl isobutyl ether (MIBE) or isobutene from methanol-isobutanol mixtures. The precursor salt was synthesized and provided by Dr. T. H. Kalantar of the M.E. Pruitt Research Center, Dow Chemical Co., Midland, MI 48674. Molecular modeling of the catalyst synthesis steps and of the alcohol coupling reaction is being carried out. A representation of the methyl transfer from the surface activated methanol molecule (left) to the activated oxygen of the isobutanol molecule (right) to form an ether linkage to yield MIBE is shown.

Kamil Klier; Richard G. Herman; James G.C. Shen; Qisheng Ma

2000-08-31T23:59:59.000Z

109

7198 J. Org. Chem. 1995,60, 7198-7208 Gas Phase Decomposition of Conjugate Acid Ions of Simple  

E-Print Network [OSTI]

(MTBE),ethyl (ETBE),n-propyl,isopropyl,and isobutyl tert-butyl ethers have been examined experimentally spectroscopy (MIKES) experiments on deuterated ions from MTBE and ETBE. Mechanistic possibilities are probed tert-amyl ether and its deuterated analogues. Protonated MTBE displays a single unimolecular

Morton, Thomas Hellman

110

energy savings by the use of mtbe to replace alkylate in automotive gasolines  

SciTech Connect (OSTI)

This paper presents data on the differences in energy consumption in the production of leaded and unleaded AI-93 gasolines with various blend components. The authors investigate as high-octane components certain products that are more effective in use and less energy-consuming in production in comparison with alkylate. In particular, methyl tert-butyl ether (MTBE) is discussed; it is not poisonous, it has a high heat of combustion, and it does not attack materials of construction. The addition of 11% MTBE to gasoline lowers the cold start temperature of engines by 10-12 degrees. Moreover, no adjustment of the carburetor is required for the changeover to gasoline with 11% MTBE.

Englin, B.A.; Emel'yanov, V.E.; Terent'ev, G.A.; Vinogradov, A.M.

1986-07-01T23:59:59.000Z

111

Removal of MTBE and other organic contaminants from water by sorption to high silica zeolites  

SciTech Connect (OSTI)

Select zeolites with high SiO{sub 2}/Al{sub 2}O{sub 3} ratios were shown to effectively remove methyl tert-butyl ether (MTBE), chloroform, and trichloroethylene (TCE) from water. In laboratory studies using batch sorption equilibria, high Si large-port mordenite and ZSM-5 (silicalite) were found to have sorption properties for MTBE and TCE superior to activated carbon. for example, at an equilibrium solution concentration of 100 {micro}g/L, high Si mordenite retained 8--12x more MTBE than either of two powdered activated carbons used as reference sorbents. Sorption results also highlight the importance of pore size and SiO{sub 2}/Al{sub 2}O{sub 3} ration on contaminant removal efficiencies by zeolites.

Anderson, M.A.

2000-02-15T23:59:59.000Z

112

APPLICATIONS OF LAYERED DOUBLE HYDROXIDES IN REMOVING OXYANIONS FROM OIL REFINING AND COAL MINING WASTEWATER  

SciTech Connect (OSTI)

Western Research Institute (WRI), in conjunction with the U.S. Department of Energy (DOE), conducted a study of using the layered double hydroxides (LDH) as filter material to remove microorganisms, large biological molecules, certain anions and toxic oxyanions from various waste streams, including wastewater from refineries. Results demonstrate that LDH has a high adsorbing capability to those compounds with negative surface charge. Constituents studied include model bacteria, viruses, arsenic, selenium, vanadium, diesel range hydrocarbons, methyl tert-butyl ether (MTBE), mixed petroleum constituents, humic materials and anions. This project also attempted to modify the physical structure of LDH for the application as a filtration material. Flow characterizations of the modified LDH materials were also investigated. Results to date indicate that LDH is a cost-effective new material to be used for wastewater treatment, especially for the treatment of anions and oxyanions.

Song Jin; Paul Fallgren

2006-03-01T23:59:59.000Z

113

Coadsorption of methanol and isobutene on HY zeolite  

SciTech Connect (OSTI)

In order to develop a better understanding of methyl tert-butyl ether (MTBE) synthesis on zeolites, the coadsorption of methanol and isobutene on HY zeolite was investigated using IR spectroscopy. Initial adsorption of isobutene alone at 35{degree}C led to rapid oligomerization yielding strongly bound oligomers. The subsequent coadsorption of methanol did not induce any changes in the zeolite-adsorbate complexes. TPD following the coadsorption showed that the Bronsted acid sites could be restored by temperature treatment above approximately 300{degree}C. When methanol was adsorbed first and isobutene was subsequently coadsorbed, MTBE was formed even at 35{degree}C on the catalyst surface. MTBE desorbed easily at a temperature of 70{degree}C, restoring a major fraction of the Bronsted acid sites. Methanol was concluded to decrease the probability of oligomerization by effectively competing for the acid sites. 34 refs., 6 figs.

Kogelbauer, A.; Goodwin, J.G. Jr. [Univ. of Pittsburgh, PA (United States); Lercher, J.A. [Univ. of Twente, Enschede (Netherlands)

1995-05-25T23:59:59.000Z

114

Autoignition behavior of lean mixtures: Chemical and thermodynamics effects  

SciTech Connect (OSTI)

Knock characteristics of natural gas (NG), 89 octane unleaded gasoline, 2,2-dimethyl butane (22DMB), and methyl tert-butyl ether (MTBE) in stoichiometric and lean fuel-air mixtures were studied in a production 4-cylinder automotive engine. The Intake Temperature at the Knock Limit (ITKL) was different for each fuel but always higher in lean mixtures. Gasoline and 22DMB exhibited much greater increases in ITKL than MTBE and NG at lean conditions. Surprisingly, for lean mixtures 22DMB exhibited higher ITKL than MTBE and was almost as high as NG. Comparison with detailed numerical modelling was very favorable. Computations show that both differences in chemistry and end-gas temperature and pressure histories are responsible for these trends. This behavior is interpreted in terms of the Negative Temperature Coefficient behavior of hydrocarbon oxidation. The implication of these results for the specification of optimal fuels for lean-burn engine is discussed.

Ronney, P.D.; Shoda, M.; Waida, S.T. [Princeton Univ., NJ (United States). Dept. of Mechanical and Aerospace Engineering; Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Lab., CA (United States)

1992-01-15T23:59:59.000Z

115

Korean oxygenates rule sparks MTBE capacity plans  

SciTech Connect (OSTI)

The Korean government`s strict standard for gasoline sold domestically is expected to have a significant impact on the methyl tert-butyl ether (MTBE) market. The mandate-requiring gasoline oxygen content of 0.5% this year, 0.75% by 1996, and 1.0% by 1998-has sparked a rush by Korean refineries to build new MTBE plants. If expansion plans are carried out, Korea`s MTBE capacity will increase from 280,000 m.t./year to 650,000 m.t./year by 1996, far surpassing predicted demand. Honam Oil, part of the Lucky Group, plans startup of a 100,000-m.t./year unit at Yeochon by early 1996. In addition, by the end of 1996 Ssangyong Oil will bring a 100,000-m.t./year unit onstream.

Kim, Hyung-Jin

1994-06-15T23:59:59.000Z

116

Ecofuel plans MTBE plant in Italy  

SciTech Connect (OSTI)

Ecofuel (Milan), an ENI company, is evaluating construction of a new methyl tert-butyl ether (MTBE) plant in Italy, but has shelved plans for a world-scale MTBE unit in Mexico. The Italian unit is tied to ethylene expansion now under way. Later this year EniChem (Milan), a sister company, is due to complete construction of a 360,000-m.t./year cracker at Brindisi. The C{sub 4} stream available there and from the existing cracker at Priolo in Sicily should provide enough feed for a unit of up to 100,000 m.t./year of MTBE capacity. Some of the feedstock could also come from the Ravenna cracker.

Alperowicz, N.

1992-04-29T23:59:59.000Z

117

Proton NMR analysis of octane number for motor gasoline: Part V  

SciTech Connect (OSTI)

A method to predict the octane number of automobile gasoline containing methyl tert-butyl ether (MTBE) by proton magnetic resonance (PMR) spectrometry was studied. Samples of gasoline whose octane numbers had been identified according to the ASTM standards (commercially available premium gasoline to which MTBE was added at rates of 7 vol % and 14 vol %) were used in this investigation of the effect of MTBE on the octane number. The findings were utilized to introduce a term regarding MTBE into the previously reported linear regression equation for estimating the octane number from the PMR spectrum, and the appropriateness of the linear regression equation was assessed. As a result the MTBE contents in the sample were determined with satisfactory accuracy by using a standard addition method, and a linear regression equation reflecting the effect of MTBE was obtained. These achievements are reported. 11 refs., 3 figs., 5 tabs.

Ichikawa, M.; Nonaka, N.; Amano, H.; Takada, I.; Ishimori, S. [Suzuki Motor Corp., Hamamatsu (Japan); Andoh, H.; Kumamoto, K. [Showa Shell Sikiyu Tokyo (Japan)

1992-10-01T23:59:59.000Z

118

A screening model for evaluating the degradation and transport of MTBE and other fuel oxygenates in the subsurface  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE) has received high attention as it contributed to cleaner air and contaminated thousands of underground storage tank sites. Because MTBE is very water soluble, it is more difficult to remove from water by conventional remediation techniques. Therefore, biodegradation of MTBE has become a remediation alternative. In order to understand the transport and transformation processes, they present a closed form solution as a screening tool in this paper. The possible reaction pathways of first-order reactions are described as a reaction matrix. The singular value decomposition is conducted analytically to decouple the partial differential equations of the multi-species transport system coupled by the reaction matrix into multiple independent subsystems. Therefore, the complexity of mathematical description for the reactive transport system is significantly reduced and analytical solutions may be previously available or easily derived.

Sun, Y; Lu, X

2004-04-20T23:59:59.000Z

119

MTBE, ethanol rules come under fire  

SciTech Connect (OSTI)

EPA is facing stiff challenges to the mandates for methyl tert-butyl ether (MTBE) and ethanol in its reformulated gasoline (RFG) program. Wisconsin officials are receiving hundreds of complaints about the alleged health effects and other problems with MTBE added to gasoline, and Gov. Tommy Thompson is demanding that EPA suspend the RFG program until April 1. Rep. James Sensenbrenner (R., WI) is threatening to introduce a bill to repeal the program in Wisconsin if EPA does not comply. However, EPA administrator Carol Browner says the agency will {open_quotes}defer any decision{close_quotes} on the request. EPA has sent technical experts to Milwaukee to respond to and monitor citizens` complaints.

Begley, R.

1995-03-01T23:59:59.000Z

120

Ecological hazards of MTBE exposure: A research agenda  

SciTech Connect (OSTI)

Fuel oxygenates are used in metropolitan areas across the United States in order to reduce the amount of carbon monoxide released into the atmosphere during the winter. The most commonly used fuel oxygenate is Methyl tert-butyl ether (MTBE). Its widespread use has resulted in releases into the environment. To date there has been only minimal effort to investigate ecological impacts caused by exposure to concentrations of MTBE typically found in environmental media. Research into the potential for MTBE to adversely affect ecological receptors is essential. Acquisition of such baselines data is especially critical in light of continuing inputs and potential accumulation of MTBE in environmental media. A research Agenda is included in this report and addresses: Assessing Ecological Impacts, Potential Ecological Impacts of MTBE (aquatic organisms, terrestrial organisms), Potential Ecological Endpoints, and A Summary of Research Needs.

Carlsen, T.; Hall, L.; Rice, D.

1997-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Gas phase synthesis of MTBE on triflic-acid-modified zeolites  

SciTech Connect (OSTI)

The gas phase synthesis of MTBE (methyl tert-butyl ether) was studied using three series of triflic acid (TFA)-modified zeolites, the parent materials being HY, H-mordenite, and HZSM-5. Impregnation with TFA was found to enhance MTBE synthesis activity only for the large-pore zeolite Y and only up to a certain extent of modification. A high level of TFA modification caused a reduction in activity, apparently due to blockage of the active sites by TFA molecules and extra-lattice Al formed during the modification process. The mechanism of activity enhancement by TFA modification appears to be related to the formation of extra-lattice Al rather than the direct presence of TFA. 20 refs., 6 figs., 1 tab.

Nikolopoulos, A.A.; Kogelbauer, A.; Goodwin, J.G. Jr. [Univ. of Pittsburgh, PA (United States)] [and others] [Univ. of Pittsburgh, PA (United States); and others

1996-01-01T23:59:59.000Z

122

Lyondell`s new isobutylene route could fuel an MTBE capacity boost  

SciTech Connect (OSTI)

Driven by the hot growth prospects for methyl tert-butyl ether (MTBE), Lyondell Petrochemical (Houston) has developed a route to isobutylene it claims can produce the MTBE feedstock at half the capital cost of alternative synthesis technology. If proved, the process will be used in a new 7500-10,000 bbl/day MTBE plant at Channelview, TX. Lyondell also hopes to license the technology. {open_quotes}With expanding MTBE capacity, we will have to have new routes to isobutylene,{close_quotes} says Bob G. Gower, president and CEO of Lyondell. {open_quotes}We think this is a good fit within Lyondell, but also that it is important technology.{close_quotes} Gower declines to detail its specifics, but says it is a one-step isomerization of n-butenes to isobutylene. The firm has tested the process at a pilot unit and plans a demonstration unit in 1992.

Rotman, D.; Wood, A.

1992-03-25T23:59:59.000Z

123

Photocatalytic reactions of oxygenates on tropospheric oxide particles  

SciTech Connect (OSTI)

Oxygenates such as ethanol and tert-butyl methyl ether (MTBE) are finding increased use as additives to fuels. The relative merits of ethanol and MTBE have become the focus of intense debate with their ultimate fate as fugitive emissions representing one aspect of this controversy. Both species are known to react homogeneously with photogenerated OH radicals. Here we show that both can also photoreact on suspended solid particulates in the atmosphere with rates comparable to those of OH reactions. Heterogeneous reactions of ethanol yield acetaldehyde and those of MTBE give isobutene and formaldehyde (carcinogenic). Experiments by spectroscopic and kinetic techniques show that the active phases in fly ash are Fe and Ti oxides. In addition, the effects of humidity and alkali addition on the activity and selectivity of these reactions are also discussed. This work appears to be the first demonstration that volatile organic compounds can react as fast by a heterogeneous mechanism as by a homogeneous one in the atmosphere.

Idriss, H.; Seebauer, E.G.; Miller, A. [Univ. of Illinois, Urbana, IL (United States)

1996-10-01T23:59:59.000Z

124

Snamprogetti signs MTBE contracts  

SciTech Connect (OSTI)

Snamprogetti (Milan) will use a Russian-developed dehydrogenation process in a world-scale methyl tert-butyl ether (MTBE) plant it is to build at Arzew, Algeria for a previously announced joint venture of Sonatrach (Algiers), Total (Paris), and Ecofuel (Milan). The 600,000-m.t./year plant will be the first in the West to use the improved Snamprogetti-Yarsintez fluidized-bed dehydrogenation (FBD) technology proven on a demonstration plant at Yaroslavl, Russia. The process has also been selected for use in Oxyfuel Corp.`s 500,000-m.t./year MTBE plant near Beaumont, TX. Although the environmental permit is already in place, final agreement for this project has not yet been signed.

Alperowicz, N.

1992-04-15T23:59:59.000Z

125

EPA proposal sets MTBE back  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE) producers were looking for a boost from the official New Year`s start of EPA`s reformulated gasoline (RFG) program. But that prospect has been dimmed by an EPA-proposal-in reaction to concerns about RFG prices-to allow states to withdraw from the program. The states that have opted to out make up 5%-6% of the total RFG pool says Arthur Zadronzy, director/government outreach for MTBE producer Arco Chemical. {open_quotes}This is not a major hit, but it is one we have felt,{close_quotes} he says. Despite the state and EPA actions, MTBE producers are not worried about long-term consequences.

Lucas, A.

1995-01-04T23:59:59.000Z

126

Vapor-liquid equilibria of hydrocarbons and fuel oxygenates. 2  

SciTech Connect (OSTI)

Vapor-liquid equilibrium data for methyl tert-butyl ether (MTBE) + 1-heptene, MTBE + four-component gasoline prototype, ethanol + four-component gasoline prototype, and separately MTBE and ethanol with the Auto/Oil Air Quality Improvement Research Gasoline Blend A are reported. Small additions of MTBE have a very small effect on the total equilibrium pressure of this gasoline blend, and at most temperatures will decrease this pressure. In contrast, small additions of ethanol to this gasoline blend result in a significant increase in the equilibrium pressure at all temperatures. Analysis shows that the vapor-liquid equilibrium data for the MTBE-containing systems are easily correlated using a modified Peng-Robinson equation of state with conventional van der Waals one-fluid mixing rules. Data for mixtures containing ethanol cannot be accurately correlated in this way.

Bennett, A.; Lamm, S.; Orbey, H.; Sandler, S.I. (Univ. of Delaware, Newark (United States))

1993-04-01T23:59:59.000Z

127

Iran plans huge private sector MTBE plant  

SciTech Connect (OSTI)

An export-oriented 1-million m.t./year methyl tert-butyl ether (MTBE) plant is planned as one of Iran`s private sector investment projects. State-owned National Petrochemical Co (NPC; Tehran) and the Dubai-based Iranian businessman Abdul Wahab Galadari have signed a letter of intent allowing Galadari to develop the venture. Colt Engineering (Calgary, AL) is assisting Galadari with costs, planning and technology selection for the estimated $300-million plus venture. An important meeting with NPC is scheduled end of this month, says Galadari, and a financial package should be put together by end of March or April. The facility will most likely be wholly-owned by the Galadari family, roughly 50% by members resident in Iran and the remainder by the Dubai-based concern A.W. Galadari Sons. NPC says it may take a token shareholding in the venture.

Alperowicz, N.

1992-01-15T23:59:59.000Z

128

Self-ignition of S.I. engine model fuels: A shock tube investigation at high pressure  

SciTech Connect (OSTI)

The self-ignition of several spark-ignition (SI) engine fuels (iso-octane, methanol, methyl tert-butyl ether and three different mixtures of iso-octane and n-heptane), mixed with air, was investigated experimentally under relevant engine conditions by the shock tube technique. Typical modes of the self-ignition process were registered cinematographically. For temperatures relevant to piston engine combustion, the self-ignition process always starts as an inhomogeneous, deflagrative mild ignition. This instant is defined by the ignition delay time, {tau}{sub defl}. The deflagration process in most cases is followed by a secondary explosion (DDT). This transition defines a second ignition delay time, {tau}{sub DDT}, which is a suitable approximation for the chemical ignition delay time, if the change of the thermodynamic conditions of the unburned test gas due to deflagration is taken into account. For iso-octane at p = 40 bar, a NTC (negative temperature coefficient), behavior connected with a two step (cool flame) self-ignition at low temperatures was observed. This process was very pronounced for rich and less pronounced for stoichiometric mixtures. The results of the {tau}{sub DDT} delays of the stoichiometric mixtures were shortened by the primary deflagration process in the temperature range between 800 and 1,000 K. Various mixtures of iso-octane and n-heptane were investigated. The results show a strong influence of the n-heptane fraction in the mixture, both on the ignition delay time and on the mode of self-ignition. The self-ignition of methanol and MTBE (methyl tert-butyl ether) is characterized by a very pronounced initial deflagration. For temperatures below 900 K (methanol: 800 K), no secondary explosion occurs. Taking into account the pressure increase due to deflagration, the measured delays {tau}{sub DDT} of the secondary explosion are shortened by up to one order of magnitude.

Fieweger, K.; Blumenthal, R.; Adomeit, G. [RWTH, Aachen (Germany). Inst. fuer Allegemeine Mechanik] [RWTH, Aachen (Germany). Inst. fuer Allegemeine Mechanik

1997-06-01T23:59:59.000Z

129

Supporting Information A scalable synthesis of the (S)-4-(tert-butyl)-2-(pyridin-2-yl)-4,5-dihydrooxazole  

E-Print Network [OSTI]

with a three-pitched curved blade, an internal thermometer, and a reflux condenser equipped with a two a steam of N2. The flask was charged with (S)-tert-leucine (15.08 g, 115.0 mmol, 1.00 equv, 99% ee and replaced by a condenser and the reaction was heat to reflux (80 °C oil bath). After 20 h the reaction

Stoltz, Brian M.

130

High octane ethers from synthesis gas-derived alcohols. Quarterly technical progress report, April--June 1992  

SciTech Connect (OSTI)

The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobutyl ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-l-propanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers. The last stage of the synthesis involves direct coupling of synthesis gas-derived methanol and isobutanol that has been demonstrated by us to occur over superacid catalysts to yield methyl isobutyl ether (MIBE) at moderate pressures and a mixture of methanol and isobutene at low pressures. MIBE is an isomer of MTBE and a process is proposed whereby MTBE from the two alcohols is maximized and MIBE is minimized. This will be achieved by the proper choice of reaction conditions, i.e. intermediate pressures, and of inorganic acid catalysts that are stable at temperatures higher than 200{degree}C, at which the carbonium ion reaction coupling of the two alcohols to MTBE is more effective than the oxonium ion or ester reaction coupling to MIBE. Both organic and inorganic catalysts will be investigated, and the better catalysts of these classes will be subjected to long term performance studies. The long term performance studies of the combined process will extend to 1000 hr and detailed analytical data for all products will be provided.

Klier, K.; Herman, R.G.; Feeley, O.C.; Johansson, M.A.

1992-07-01T23:59:59.000Z

131

Capture isobutylene with glycol  

SciTech Connect (OSTI)

The separation of butenes present in C-4 streams (generated as a result of steam or catalytic cracking) is becoming increasingly important as the butenes find expanded applications in the production of methyl-t-butyl ether (MTBE), methyl methacrylate, butyl rubber, and linear low-density polyethylene. Available methods of separation include selective extraction with a liquid solvent (usually an acid); the use of addition reactions with suitable alcohols, acids, or water; selective polymerization and physical separation by absorbents. Three currently important separation processes for isobutylene production are an extraction route using mineral acid, the dehydration of tert-butanol, and the cracking of MTBE. As part of the research into solid acid catalysis for the generation of glycol tert-butyl monoethers, the authors have demonstrated an alternative C-4 separation process using solid inorganic acid catalysts and involving the intermediate preparation of glycol ethers. This new C-4 separation scheme could be particularly attractive to existing glycol producers who may also have a market, or internal need, for glycol monoalkyl ethers, as well as those who do not have MTBE capacity but still require pure isobutylene as a chemical intermediate or comonomer building block. The process is described.

Knifton, J.F. (Texaco Chemical's Austin Research Lab. TX (United States))

1994-05-01T23:59:59.000Z

132

Aza crown ether compounds as anion receptors  

DOE Patents [OSTI]

A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the new family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of LI{sup +} ion in alkali metal batteries. 3 figs.

Lee, H.S.; Yang, X.O.; McBreen, J.

1998-08-04T23:59:59.000Z

133

Near-Infrared Electrochromism in Electroactive Pentacenediquinone-Containing Poly(aryl ether)s  

E-Print Network [OSTI]

Near-Infrared Electrochromism in Electroactive Pentacenediquinone-Containing Poly(aryl etherVed October 21, 2005 The synthesis and near-infrared electrochromic properties of pentacenediquinone-infrared electrochromic properties of pentacenediquinone-containing poly(aryl ether)s were studied

Wan, Xin-hua

134

Crown Ethers in Graphene Bring Strong, Selective Binding | ornl...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Materials Characterization Crown Ethers in Graphene Bring Strong, Selective Binding November 14, 2014 Schematic showing a graphene sheet containing an array of ideal crown ethers....

135

CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS  

SciTech Connect (OSTI)

A tungstena-zirconia (WZ) catalyst has been investigated for coupling methanol and isobutanol to unsymmetrical ethers, i.e. methyl isobutyl ether (MIBE) and compared with earlier studied sulfated-zirconia (SZ) and Nafion-H catalysts. In all cases, the ether synthesis mechanism is a dual site S{sub N}2 process involving competitive adsorption of reactants on proximal acid sites. At low reaction temperatures, methylisobutylether (MIBE) is the predominant product. However, at temperatures >135 C the WZ catalyst is very good for dehydration of isobutanol to isobutene. The surface acid sites of the WZ catalyst and a Nafion-H catalyst were diagnosed by high resolution X-ray photoelectron spectroscopy (XPS) of N 1s shifts after adsorption of amines. Using pyridine, ethylenediamine, and triethylamine, it is shown that WZ has heterogeneous strong Broensted acid sites. Theoretical study located the transition state of the alcohol coupling reaction on proximal Broensted acid sites and accounted well for XPS core-level shifts upon surface acid-base interactions. While computations have not been carried out with WZ, it is shown that the SZ catalyst is a slightly stronger acid than CF{sub 3}SO{sub 3}H (a model for Nafion-H) by 1.3-1.4 kcal/mol. A novel sulfated zirconia catalyst having proximal strong Broensted acid sites was synthesized and shown to have significantly enhanced activity and high selectivity in producing MIBE or isobutene from methanol/isobutanol mixtures. The catalyst was prepared by anchoring 1,2-ethanediol bis(hydrogen sulfate) salt precursor onto zirconium hydroxide, followed by calcination to remove the -(CH{sub 2}CH{sub 2})- bridging residues.

Kamil Klier; Richard G. Herman; Heock-Hoi Kwon; James G. C. Shen; Qisheng Ma; Robert A. Hunsicker; Andrew P. Butler; Scott J. Bollinger

2003-03-01T23:59:59.000Z

136

Ethers have good gasoline-blending attributes  

SciTech Connect (OSTI)

Because of their compatibility with hydrocarbon gasoline-blending components, their high octane blending values, and their low volatility blending values, ethers will grow in use as gasoline blending components. This article discusses the properties of ethers as blending components, and environmental questions.

Unzelman, G.H.

1989-04-10T23:59:59.000Z

137

MTBE still in poor health, despite the Clean Air Act  

SciTech Connect (OSTI)

After the second winter oxygenated fuels program of the 1990 Clean Air Act, producers of methyl tert-butyl ether (MTBE) are still feeling the chill of poor profitability. Despite the strong demand growth for MTBE to meet oxygen requirements in reformulated gasoline (RFG), oversupply still dogs the market. That, combined with a run-up in feedstock prices, has seen margins for MTBE markers all but evaporate. And it seems matters are likely to get worse before they get better. This week, Belvieu Environmental Fuels (BEF; Houston) expects to startup its 15,000-bbl/day MTBE plant at Mont Belvieu, TX. In late July, Texaco will start up its 15,000-bbl/day MTBE/propylene oxide (PO) plant at Port Neches, TX. In addition, a rash of refinery-based MTBE and tert-amyl methyl ether projects are nearing completion. {open_quotes}Profitability in MTBE has been extremely poor,{close_quotes} says Marvin O. Schlanger, president of Arco Chemical Americas, the largest MTBE producer. There has, however, been some recent recovery on the spot market, with MTBE moving from less than 60 cts/gal to near cash-cost levels of 70 cts/gal. But contract prices remain depressed, and strength in butane and methanol pricing have all buy wiped out any gains in MTBE.

Wood, A.

1994-05-25T23:59:59.000Z

138

Purification of aqueous cellulose ethers  

SciTech Connect (OSTI)

Manufacture of cellulose ethers usually involves high amounts of salt by-products. For application of the product, salt must be removed. In this work, we have studied the injection of high-pressure CO{sub 2} into an aqueous polymer-salt solution; we find that upon addition of isopropanol in addition to CO{sub 2}, the solution separates into two phases. One phase is rich in polymer and water, and the other phase contains mostly isopropanol, water and CO{sub 2}. The salt distributes between the two phases, thereby offering interesting possibilities for development of a new purification process for water-soluble polymers. This work presents experimental phase-equilibrium data for hydroxyethyl cellulose and sodium carboxymethyl cellulose with sodium acetate and potassium sulfate, respectively, in the region 40{degree}C and 30 to 80 bar. Based on these data, we suggest a process for the manufacture and purification of water-soluble cellulose ethers. 15 refs., 14 figs., 9 tabs.

Bartscherer, K.A.; de Pablo, J.J.; Bonnin, M.C.; Prausnitz, J.M.

1990-07-01T23:59:59.000Z

139

Water Research 37 (2003) 37563766 Seasonal and daily variations in concentrations of methyl-  

E-Print Network [OSTI]

by volume to gasoline from November to February, and blending 11% MTBE by volume during the rest of the year; accepted 24 March 2003 Abstract Methyl-tertiary-butyl ether (MTBE), an additive used to oxygenate gasoline of gasoline-powered watercraft. This paper documents and explains both seasonal and daily variations in MTBE

Toran, Laura

140

Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 6, January 1, 1992--March 31, 1992  

SciTech Connect (OSTI)

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl ether (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: (1) Addition of isobutylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch. (2) Addition of isobutylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst. (3) Addition of methanol to slurry phase FT synthesis making iso-olefins. During the sixth quarter we completed the construction of the slurry bubble column reactor (SBCR), conducted initial shake-down experiments in a cold-flow mode, and finalized the selection process of the acid catalysts for conversion of syngas-produced alcohols and isobutylene to MTBE (scheme 2). Tasks 3, 4, and 5 are awaiting complete implementation of the SBCR system.

Marcelin, G.

1992-06-24T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Process for making propenyl ethers and photopolymerizable compositions containing them  

DOE Patents [OSTI]

Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} (V) wherein n is an integer from one to six and A is selected from cyclic ethers, polyether, and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

Crivello, J.V.

1996-01-23T23:59:59.000Z

142

Selecting activated carbon for water and wastewater treatability studies  

SciTech Connect (OSTI)

A series of follow-up investigations were performed to produce data for improving the four-indicator carbon selection method that we developed to identify high-potential activated carbons effective for removing specific organic water pollutants. The carbon's pore structure and surface chemistry are dependent on the raw material and the activation process. Coconut carbons have relatively more small pores than large pores; coal and apricot nutshell/walnut shell fruit carbons have the desirable pore structures for removing adsorbates of all sizes. Chemical activation, excessive activation, and/or thermal reactivation enlarge small pores, resulting in reduced phenol number and higher tannic acid number. Activated carbon's phenol, iodine, methylene blue, and tannic acid numbers are convenient indicators of its surface area and pore volume of pore diameters < 10, 10-15, 15-28, and > 28 angstrom, respectively. The phenol number of a carbon is also a good indicator of its surface acidity of oxygen-containing organic functional groups that affect the adsorptive capacity for aromatic and other small polar organics. The tannic acid number is an indicator of carbon's capacity for large, high-molecular-weight natural organic precursors of disinfection by-products in water treatment. The experimental results for removing nitrobenzene, methyl-tert-butyl ether, 4,4-bisphenol, humic acid, and the organic constituents of a biologically treated coking-plant effluent have demonstrated the effectiveness of this capacity-indicator-based method of carbon selection.

Zhang, W.; Chang, Q.G.; Liu, W.D.; Li, B.J.; Jiang, W.X.; Fu, L.J.; Ying, W.C. [East China University of Chemical Technology, Shanghai (China)

2007-10-15T23:59:59.000Z

143

Fast photoreactions of ethanol and MTBE on tropospheric metal oxide particles  

SciTech Connect (OSTI)

Ethanol (EtOH) and tert-Butyl methyl ether (MTBE) are both finding increased use as oxygenated additives to fuels. However, the environmental fate in the troposphere of these species is unclear when they escape as fugitive emissions. In several locations there are reports of human illness in response to MTBE in particular. Volatile organic compounds (VOC`s) such as these are generally thought to react by a variety of homogeneous free-radical mechanisms, usually beginning with attack by OH radical. However, we show by laboratory kinetic studies that the heterogeneous photoreaction on solid suspended metal-oxide particulates such as fly ash proceeds with a comparable rate, especially in urban environments. EtOH reacts to form acetaldehyde, and EtOH forms isobutene, methanol, and formaldehyde. Our work appears to be the first-ever demonstration that VOC`s can react as fast by a heterogeneous mechanism as by a homogeneous one in the atmosphere. Experiments by various optical and kinetic techniques show that the active phases in fly ash are Fe oxides, which are fairly abundant in other atmospheric particulates as well.

Idriss, H.; Seebauer, E.G. [Univ. of Illinois, Urbana, IL (United States)

1995-12-31T23:59:59.000Z

144

High-temperature ignition of propane with MTBE as an additive: Shock-tube experiments and modeling  

SciTech Connect (OSTI)

Ignition of propane has been studied in a shock tube and by computational modeling to determine the effect of methyl tert-butyl ether (MTBE) as a fuel additive. MTBE and isobutene were added in amounts up to 25% of the fuel to propane-oxygen-argon mixtures in shock-tube experiments covering a range of temperatures between 1450 and 1800 K. Ignition delays were measured from chemiluminescence at 432 nm due to excited CH radicals. The temperature dependence of the ignition rates was analyzed to yield Arrhenius parameters of E{sub a}{approximately}40 kcal/mol and log (A){approximately} 9.0 sec{sup {minus}1} for the overall reaction. Reactions involving MTBE and its decomposition products were combined with an established propane mechanism in a numerical model to describe the kinetic interaction of this additive with a typical hydrocarbon fuel. The experiments and the kinetic model both show that MTBE and isobutene retard propane ignition with nearly equal efficiency. The kinetic model demonstrates that isobutene kinetics are responsible for inhibition by both MTBE and isobutene, and the specific elementary reactions which produce this behavior are identified.

Gray, J.A. (Sandia National Labs., Livermore, CA (United States)); Westbrook, C.K. (Lawrence Livermore National Lab., CA (United States))

1991-01-01T23:59:59.000Z

145

Meeting the challenge of MTBE biodegradation  

SciTech Connect (OSTI)

Oxygenated and reformulated gasolines have been developed in response to air pollution control regulations targeted at reducing carbon monoxide emissions and photochemical air pollution. The 1990 Clean Air Act Amendments required the addition of fuel oxygenates to gasoline in areas where the level of carbon monoxide exceeded national ambient air quality standards. In the South Coast Air Basin gasoline containing oxygenated compounds has been in use since the late 1980`s. One oxygenated fuel additive most often selected by producers to meet the requirements is methyl tert-butyl ether (MTBE). However, large production numbers associated with MTBE production, combined with the compound`s high water solubility, chemical stability, and toxicity, make it a potentially important groundwater pollutant. The County Sanitation District of Los Angeles, Joint Water Pollution Control Plant in Carson, California is one of the few wastewater treatment plants in the nation that receives refinery wastewater discharge. It has operated several pilot-scale compost-based biofilters for control of various volatile organic contaminants throughout the plant since a 1991 joint study with the University of California, Davis. After one year of operation, one of the biofilters spontaneously developed the ability to degrade MTBE. The paper describes the collaborative efforts to determine the feasibility of transferring the degrading microbial population from the solid to liquid phase, without loss of activity, and to determine some of the environmental requirements necessary for survival of the microbial culture.

Eweis, J.B.; Chang, D.P.Y.; Schroeder, E.D.; Scow, K.M. [Univ. of California, Davis, CA (United States); Morton, R.L.; Caballero, R.C. [Los Angeles County Sanitation Districts, Carson, CA (United States). Joint Water Pollution Control Plant

1997-12-31T23:59:59.000Z

146

Synthesis of octane enhancers during slurry-phase Fischer-Tropsch. Quarterly technical progress report No. 7, April 1, 1992--June 30, 1992  

SciTech Connect (OSTI)

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: addition of i-butylene during the formation of methanol and/or higher alcohols directly from CO and H{sub 2} during slurry-phase Fischer-Tropsch; addition of i-butylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and addition of methanol to slurry phase FT synthesis making iso-olefins. During the seventh quarter we continued the shake down experiments for the SBCR and conducted an initial aborted run. We have also re-started experiments on Scheme 1, i.e., the addition of iso-butylene during CO hydrogenation. Using a dual bed arrangement, we have demonstrated the synthesis of MTBE from syngas and iso-butylene.

Marcelin, G.

1992-09-24T23:59:59.000Z

147

Interdisciplinary investigation of subsurface contaminant transport and fate at point-source releases of gasoline containing MTBE  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE) is commonly found at concentrations above the current U.S. Environmental Protection Agency draft lifetime health advisory for drinking water (20 to 200 micrograms per liter) at many point-source gasoline release sites. MTBE is significantly more persistent than benzene, toluene, ethyl-benzene and xylenes (BTEX) in the subsurface. Therefore, evaluation of the implications of its presence in gasoline to monitored natural attenuation and engineered bioremediation alternatives is warranted. An interdisciplinary, field-based investigation of the subsurface transport and fate of MTBE and petroleum hydrocarbons is being conducted by the U.S. Geological Survey (USGS) Toxic Substances Hydrology Program at the site of an underground gasoline storage-tank release near Beaufort, South Carolina. The objective of the investigation is to provide a systematic evaluation of natural attenuation of MTBE compared to BTEX. Results of the field and laboratory studies at this site will be generalized to a broader range of hydrogeochemical conditions through experiments at other sites. Furthermore, newly developed methods of analysis can be applied to sites across the Nation. This investigation of MTBE at point-source release sites is coordinated with investigations of the occurrence of MTBE in shallow ground water, surface water, precipitation, and the atmosphere being conducted by the USGS National Water-Quality Assessment Program.

Buxton, H.T.; Baehr, A.L. [Geological Survey, West Trenton, NJ (United States); Landmeyer, J.E. [Geological Survey, Columbia, SC (United States)] [and others

1997-12-31T23:59:59.000Z

148

High-temperature ignition of propane with MTBE as an additive: Shock-tube experiments and modeling. Revision 1  

SciTech Connect (OSTI)

Ignition of propane has been studied in a shock tube and by computational modeling to determine the effect of methyl tert-butyl ether (MTBE) as a fuel additive. MTBE and isobutene were added to amounts up to 25% of the fuel to propane-oxygen-argon mixtures to shock-tube experiments covering a range of temperatures between 1450 and 1800 K. Ignition delays were measured from chemiluminescence at 432 nm due to excited CH radicals. The temperature dependence of the ignition rates was analyzed to yield Arrhenium parameters of E{sub a}{sup {minus}}40 kcal/mol and log(A) {sup {minus}}9.0 sec{sup {minus}1} for the overall reaction. Reactions involving MTBE and its decomposition products were combined with an established propane mechanism in a numerical model to describe the kinetic interaction of this additive with a typical hydrocarbon fuel. The experiments and the kinetic model both show that MTBE and isobutene retard propane ignition with nearly equal efficiency. The kinetic model demonstrates that isobutene kinetics are responsible for inhibition by both MTBE and isobutene, and the specific elementary reactions which produce this behavior are identified. 19 refs., 1 fig., 3 tabs.

Gray, J.A. [Sandia National Labs., Livermore, CA (United States); Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States)

1991-12-01T23:59:59.000Z

149

Effects of temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon  

SciTech Connect (OSTI)

The effects of temperature and acidic pretreatment on Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC, derived from bituminous coal) were investigated. Limiting factors in MTBE removal in GAC include the heterogeneous distribution of amended Fe, and slow intraparticle diffusive transport of MTBE and hydrogen peroxide (H{sub 2}O{sub 2}) into the 'reactive zone'. Acid pretreatment of GAC before Fe amendment altered the surface chemistry of the GAC, lowered the pH point of zero charge, and resulted in greater penetration and more uniform distribution of Fe in GAC. This led to a condition where Fe, MTBE, and H{sub 2}O{sub 2} coexisted over a larger volume of the GAC contributing to greater MTBE oxidation and removal. H{sub 2}O{sub 2} reaction and MTBE removal in GAC increased with temperature. Modeling H{sub 2}O{sub 2} transport and reaction in GAC indicated that H{sub 2}O{sub 2} penetration was inversely proportional with temperature and tortuosity, and occurred over a larger fraction of the total volume of small GAC particles (0.3 mm diameter) relative to large particles (1.2 mm diameter). Acidic pretreatment of GAC, Fe-amendment, elevated reaction temperature, and use of small GAC particles are operational parameters that improve Fenton-driven oxidation of MTBE in GAC. 29 refs., 6 figs., 1 tab.

Kan, E.; Huling, S.G. [Robert S. Kerr Environmental Research Center, Ada, OK (United States)

2009-03-01T23:59:59.000Z

150

Synthesis of MTBE during CO hydrogenation: Reaction sites required  

SciTech Connect (OSTI)

Synthesis of methyl tert-butyl ether (MTBE) during carbon monoxide (CO) hydrogenation has been studied with the following reaction schemes: (1) the addition of isobutylene during CO hydrogenation over metal catalysts active for methanol synthesis (Pd/SiO{sub 2} and Li-Pd/SiO{sub 2}) and (2) the addition of isobutylene during CO hydrogenation over a dual bed configuration consisting of Li-Pd/SiO{sub 2} and a zeolite (H-ZSM-5 or HY). The addition of isobutylene during methanol synthesis over the supported Pd catalysts indicated that MTBE cannot be formed on metal sites from a reaction of isobutylene with methanol precursors. However, addition of isobutylene to the syngas feed over a dual bed consisting of a methanol synthesis catalyst and an acid zeolite downstream of the methanol synthesis catalyst showed that MTBE can be synthesized during CO hydrogenation provided acid sites are available. In order to get higher conversions of methanol to MTBE, optimization of the acid catalyst and/or reaction conditions would be required to minimize formation of byproduct hydrocarbons.

Kazi, A.M.; Goodwin, J.G. Jr.; Marcelin, G.; Oukaci, R. [Univ. of Pittsburgh, PA (United States). Dept. of Chemical and Petroleum Engineering

1995-03-01T23:59:59.000Z

151

Intrinsic bioremediation of a BTEX and MTBE plume under mixed aerobic/denitrifying conditions  

SciTech Connect (OSTI)

A shallow Coastal Plain aquifer in rural Sampson Country, North Carolina, has been contaminated with petroleum hydrocarbon from a leaking underground storage tank containing gasoline.An extensive field characterization has been performed to define the horizontal and vertical distribution of soluble gasoline components and indicator parameters. A plume of dissolved methyl tert-butyl ether (MTBE) and the aromatic hydrocarbons benzene, toluene, ethylbenzene, and xylene isomers (BTEX) is present in the aquifer and has migrated over 600 ft from the source area. Background dissolved oxygen concentrations range from 7 to 8 mg/L, and nitrate concentrations range from 5 to 22 mg/L as N due to extensive fertilization of fields surrounding the spill. In the center of the BTEX plume, oxygen concentrations decline to less than 1 mg/L while nitrate concentrations remain high. The total mass flux of MTBE and all BTEX components decline with distance downgradient relative to a conservative tracer (chloride). At the source, the total BTEX concentration exceeds 75 mg/L while 130 ft downgradient, total BTEX concentrations are less than 4.9 mg/L, a 15-fold reduction. Toluene and ethylbenzene decline most rapidly followed by m-p-xylene, o-xylene and finally benzene. Biodegradation of TEX appears to be enhanced by the excess nitrate present in the aquifer while benzene biodegradation appears to be due to strictly aerobic processes.

Borden, R.C.; Daniel, R.A. [North Carolina State Univ., Raleigh, NC (United States). Civil Engineering Dept.

1995-09-01T23:59:59.000Z

152

Falling MTBE demand bursts the methanol bubble  

SciTech Connect (OSTI)

Methanol spot markets in Europe and the US have been hit hard by weakening demand from methyl tert-butyl ether (MTBE) producers. In Europe, spot prices for domestic T2 product have dropped to DM620-DM630/m.t. fob from early-January prices above DM800/m.t. and US spot prices have slipped to $1.05/gal fob from $1.35/gal. While chemical applications for methanol show sustained demand, sharp methanol hikes during 1994 have priced MTBE out of the gasoline-additive market. {open_quotes}We`ve learned an important lesson. We killed [MTBE] applications in the rest of the world,{close_quotes} says one European methanol producer. Even with methanol currently at DM620/m.t., another manufacturer points out, MTBE production costs still total $300/m.t., $30/m.t. more than MTBE spot prices. Since late 1994, Europe`s 3.3-million m.t./year MTBE production has been cut back 30%.

Wiesmann, G.; Cornitius, T.

1995-03-01T23:59:59.000Z

153

Synthesis of octane enhancers during slurry-phase Fischer-Tropsch  

SciTech Connect (OSTI)

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: addition of i-butylene during the formation of methanol and/or higher alcohols directly from CO and H[sub 2] during slurry-phase Fischer-Tropsch; addition of i-butylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and addition of methanol to slurry phase FT synthesis making iso-olefins. During the seventh quarter we continued the shake down experiments for the SBCR and conducted an initial aborted run. We have also re-started experiments on Scheme 1, i.e., the addition of iso-butylene during CO hydrogenation. Using a dual bed arrangement, we have demonstrated the synthesis of MTBE from syngas and iso-butylene.

Marcelin, G.

1992-09-24T23:59:59.000Z

154

High-temperature ignition of propane with MTBE as an additive: Shock-tube experiments and modeling  

SciTech Connect (OSTI)

Ignition of propane has been studied in a shock tube and by computational modeling to determine the effect of methyl tert-butyl ether (MTBE) as a fuel additive. MTBE and isobutene were added in amounts up to 25% of the fuel to propane-oxygen-argon mixtures in shock-tube experiments covering a range of temperatures between 1450 and 1800 K. Ignition delays were measured from chemiluminescence at 432 nm due to excited CH radicals. The temperature dependence of the ignition rates was analyzed to yield Arrhenius parameters of E{sub a}{approximately}40 kcal/mol and log (A){approximately} 9.0 sec{sup {minus}1} for the overall reaction. Reactions involving MTBE and its decomposition products were combined with an established propane mechanism in a numerical model to describe the kinetic interaction of this additive with a typical hydrocarbon fuel. The experiments and the kinetic model both show that MTBE and isobutene retard propane ignition with nearly equal efficiency. The kinetic model demonstrates that isobutene kinetics are responsible for inhibition by both MTBE and isobutene, and the specific elementary reactions which produce this behavior are identified.

Gray, J.A. [Sandia National Labs., Livermore, CA (United States); Westbrook, C.K. [Lawrence Livermore National Lab., CA (United States)

1991-12-31T23:59:59.000Z

155

High-resolution NMR process analyzer for oxygenates in gasoline  

SciTech Connect (OSTI)

We report a high-resolution 42-MHz[sup 1]HFT-NMR instrument that is suitable for use as a process analyzer and demonstrate its use in the determination of methyl tert-butyl ether (MTBE) in a flowing stream of gasoline. This spectrometer is based on a 55-kg permanent magnet with essentially no fringe field. A spectral resolution of 3 Hz was typically obtained for spinning samples, and this performance was only slightly degraded with flowing samples. We report a procedure for magnet drift compensation using a software procedure rather than a field-frequency lock channel. This procedure allowed signal averaging without loss of resolution. Regulatory changes to be implemented in the near future have created a need for the development of methods for the determination of MTBE and other oxygenates in reformulated gasolines. Existing methods employing gas chromatography are not fast enough for process control of a gasoline blender and suffer from other limitations. This study demonstrates that process analysis NMR is well-suited to the determination of MTBE in a simulated gasoline blender. The detection limit of 0.5 vol % MTBE was obtained with a measurement time of 1 min. The absolute standard deviation of independent determinations was 0.17% when the MTBE concentration was 10%, a nominal value. Preliminary results also suggest that the method may be applicable to gasolines containing mixtures of oxygenate additives as well as the measurement of aromatic and olefinic hydrogens. 33 refs., 9 figs.

Skloss, T.W.; Kim, A.J.; Haw, J.F. (Texas A M Univ., College Station, TX (United States))

1994-02-15T23:59:59.000Z

156

Factors influencing biological treatment of MTBE contaminated ground water  

SciTech Connect (OSTI)

Methyl tert-butyl ether (MTBE) contamination has complicated the remediation of gasoline contaminated sites. Many sites are using biological processes for ground water treatment and would like to apply the same technology to MTBE. However, the efficiency and reliability of MTBE biological treatment is not well documented. The objective of this study was to examine the operational and environmental variables influencing MTBE biotreatment. A fluidized bed reactor was installed at a fuel transfer station and used to treat ground water contaminated with MTBE and gasoline hydrocarbons. A complete set of chemical and operational data was collected during this study and a statistical approach was used to determine what variables were influencing MTBE treatment efficiency. It was found that MTBE treatment was more sensitive to up-set than gasoline hydrocarbon treatment. Events, such as excess iron accumulation, inhibited MTBE treatment, but not hydrocarbon treatment. Multiple regression analysis identified biomass accumulation and temperature as the most important variables controlling the efficiency of MTBE treatment. The influent concentration and loading of hydrocarbons, but not MTBE, also impacted MTBE treatment efficiency. The results of this study suggest guidelines for improving MTBE treatment. Long cell retention times in the reactor are necessary for maintaining MTBE treatment. The onset of nitrification only occurs when long cell retention times have been reached and can be used as an indicator in fixed film reactors that conditions favorable to MTBE treatment exist. Conversely, if the reactor can not nitrify, it is unlikely to have stable MTBE treatment.

Stringfellow, William T.; Hines Jr., Robert D.; Cockrum, Dirk K.; Kilkenny, Scott T.

2001-09-14T23:59:59.000Z

157

MTBE, methanol prices rise  

SciTech Connect (OSTI)

After several months of drifting lower in line with declining autumn gasoline prices, tabs for methyl tert-butyl ether (MTBE) have turned around. There has been no big demand surge, but consumers and traders are beginning to build up inventories in advance of a series of midwinter shutdowns and turnarounds by producers. Spot prices, which dropped as low as 75 cts/gal, have rebounded to 90 cts/gal fob. Eager for a positive glimmer, methanol producers posted a 3-cts/gal increase in contract prices this month. It marks the first upward idea since February. In that time contract prices have dropped 75% from $1.55/gal to 39 cts/gal. A hard winter has hit early in much of the US sending natural gas prices up sharply. At the same time, formaldehyde and acetic acid markets remain firm, and with MTBE rebounding, methanol producers feel entitled to a piece of the action. {open_quotes}I don`t buy into this claim that MTBE demand is up and I don`t think producers can justify even a 3-cts/gal increase,{close_quotes} says one. {open_quotes}There is nothing in the economy to warrant a run-up. Housing starts are weaker, and demand is down at least 80,000 bbl/day with the MTBE shutdown.{close_quotes}

Morris, G.D.L.; Cornitius, T.

1995-12-20T23:59:59.000Z

158

High-temperature ignition of propane with MTBE as an additive: Shock-tube experiments and modeling  

SciTech Connect (OSTI)

Ignition of propane has been studied in a shock tube and by computational modeling to determine the effect of methyl tert-butyl ether (MTBE) as a fuel additive. MTBE and isobutene were added to amounts up to 25% of the fuel to propane-oxygen-argon mixtures to shock-tube experiments covering a range of temperatures between 1450 and 1800 K. Ignition delays were measured from chemiluminescence at 432 nm due to excited CH radicals. The temperature dependence of the ignition rates was analyzed to yield Arrhenium parameters of E{sub a}{sup {minus}}40 kcal/mol and log(A) {sup {minus}}9.0 sec{sup {minus}1} for the overall reaction. Reactions involving MTBE and its decomposition products were combined with an established propane mechanism in a numerical model to describe the kinetic interaction of this additive with a typical hydrocarbon fuel. The experiments and the kinetic model both show that MTBE and isobutene retard propane ignition with nearly equal efficiency. The kinetic model demonstrates that isobutene kinetics are responsible for inhibition by both MTBE and isobutene, and the specific elementary reactions which produce this behavior are identified. 19 refs., 1 fig., 3 tabs.

Gray, J.A. (Sandia National Labs., Livermore, CA (United States)); Westbrook, C.K. (Lawrence Livermore National Lab., CA (United States))

1991-12-01T23:59:59.000Z

159

Heterogeneous models of tubular reactors packed with ion-exchange resins: Simulation of the MTBE synthesis  

SciTech Connect (OSTI)

The study of behavior of fixed-bed reactors using ion-exchange resins as catalysts was carried out by making use of a complete bidimensional heterogeneous model for the reactor, which included the resistances inside the ion-exchange resin particles, considered with a macroreticular structure. The active sites were located inside the gel phase of the resin, represented by microspheres, and on the macropores walls. The overall efficiency of such heterogeneous catalyst particles was defined by the macroeffectiveness and microeffectiveness factors accounting for the process behavior on the macropores and inside the microspheres. The synthesis of methyl tert-butyl ether, MTBE, a liquid-phase reversible exothermic reaction between methanol and isobutene, was considered as a reference case. This system was studied in the temperature range of 313--338 K, and the effect of the thermodynamic equilibrium conditions was examined. The results predicted by the complete heterogeneous model were compared with those obtained with the simple pseudohomogeneous model, which revealed higher hot spots. Moreover, a comparison between bidimensional and unidimensional models was also performed. The orthogonal collocation method was used for the discretization of the differential equations inside the catalyst particles, which were reduced from three (corresponding to the three mass balances for the three compounds, isobutene, methanol, and MTBE) to only one differential equation, by using the concept of the generalized variable.

Quinta Ferreira, R.M.; Almeida-Costa, C.A. [Univ. of Coimbra (Portugal). Dept. of Chemical Engineering; Rodrigues, A.E. [Univ. of Porto (Portugal). Dept. of Chemical Engineering

1996-11-01T23:59:59.000Z

160

Add MTBE unit ahead of alkylation  

SciTech Connect (OSTI)

Approximately three years ago, the people at Diamond Shamrock's Sunray, Texas, refinery recognized a growing demand for high octane super premium unleaded gasoline in their regional marketing area. It was apparent that they would need to change their processing scheme to meet this growing demand. After investigating several options, they decided to install an MTBE (methyl tert-butyl ether) unit upstream of their existing sulfuric acid (H/sub 2/SO/sub 4/) aklylation unit. The new unit would process olefin feed before it entered the alkylation unit. The MTBE unit was expected to improve Diamond Shamrock's gasoline pool in two ways. First, the MTBE would be an additional high octane blending stock for the gasoline pool. Second, the MTBE unit would improve the quality of the olefin stream going to the alkylation unit. Diamond Shamrock brought their MTBE unit onstream in December, 1985. The results of the combined operation exceeded expectations, producing alkylate in excess of 98 RON (Research octane number) and MTBE of 118 RON. These components significantly upgraded the refinery's capability to produce a super premium unleaded gasoline.

Masters, K.R.; Prohaska, E.A.

1988-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Study downplays health concerns  

SciTech Connect (OSTI)

A government-funded study has concluded that reformulated gasoline containing methyl tert-butyl ether (MTBE) does not increase short-term health risks when compared with gasoline that does not contain the additive. The study, performed by the Health Effects Institute (Cambridge, MA), compared data from dozens of animal, human, and epidemiological studies of health effects linked to oxygenates, including MTBE and ethanol, but did not find enough evidence to warrant an immediate reduction in oxygenate use. However, the study did recommend that additional research be conducted on possible health consequences associated with the gasoline additives, including neurotoxic effects, if oxygenates continue to be used long term. Oxygenates have been used in gasoline since 1992, when EPA mandated that several municipalities use MTBE or other oxygenates in reformulated gasoline to reduce carbon monoxide emissions and meet Clean Air Act requirements. Shortly after the program began, residents in areas where the oxygenates were used complained of nausea, headaches, and dizziness. The institute says the study--funded by EPA and the Centers for Disease Control--will be used for a broader review of gasoline oxygenates by the White House Office of Science and Technology Policy.

Stringer, J.

1996-03-13T23:59:59.000Z

162

Characterization of the Cobalamin and Fep Operons in Methylobium petrolphilum PM1  

SciTech Connect (OSTI)

The bacterium Methylobium petroleophilum PM1 is economically important due to its ability to degrade methyl tert-butyl ether (MTBE), a fuel additive. Because PM1 is a representative of all MTBE degraders, it is important to understand the transport pathways critical for the organism to survive in its particular environment. In this study, the cobalamin pathway and select iron transport genes will be characterized to help further understand all metabolic pathways in PM1. PM1 contains a total of four cobalamin operons. A single operon is located on the chromosome. Located on the megaplasmid are two tandem repeats of cob operons and a very close representative of the cob operon located on the chromosome. The fep operon, an iron transport mechanism, lies within the multiple copies of the cob operon. The cob operon and the fep operon appear to be unrelated except for a shared need for the T-on-B-dependent energy transduction complex to assist the operons in moving large molecules across the outer membrane of the cell. A genomic study of the cob and the fep operons with that of phylogenetically related organisms helped to confirm the identity of the cob and fep operons and to represent the pathways. More study of the pathways should be done to find the relationship that positions the two seemingly unrelated cob and fep genes together in what appears to be one operon.

Ewing, J

2005-09-06T23:59:59.000Z

163

8180 Phys. Chem. Chem. Phys., 2011, 13, 81808185 This journal is c the Owner Societies 2011 Cite this: Phys. Chem. Chem. Phys., 2011, 13, 81808185  

E-Print Network [OSTI]

photofragment translational spectroscopy. The tert-butyl radical was produced from flash pyrolysis of azo

Neumark, Daniel M.

164

Divinyl ether synthase gene and protein, and uses thereof  

DOE Patents [OSTI]

The present invention relates to divinyl ether synthase genes, proteins, and methods of their use. The present invention encompasses both native and recombinant wild-type forms of the synthase, as well as mutants and variant forms, some of which possess altered characteristics relative to the wild-type synthase. The present invention also relates to methods of using divinyl ether synthase genes and proteins, including in their expression in transgenic organisms and in the production of divinyl ether fatty acids, and to methods of suing divinyl ether fatty acids, including in the protection of plants from pathogens.

Howe, Gregg A. (East Lansing, MI); Itoh, Aya (Tsuruoka, JP)

2011-09-13T23:59:59.000Z

165

Divinyl ether synthase gene, and protein and uses thereof  

DOE Patents [OSTI]

The present invention relates to divinyl ether synthase genes, proteins, and methods of their use. The present invention encompasses both native and recombinant wild-type forms of the synthase, as well as mutants and variant forms, some of which possess altered characteristics relative to the wild-type synthase. The present invention also relates to methods of using divinyl ether synthase genes and proteins, including in their expression in transgenic organisms and in the production of divinyl ether fatty acids, and to methods of suing divinyl ether fatty acids, including in the protection of plants from pathogens.

Howe, Gregg A.; Itoh, Aya

2006-12-26T23:59:59.000Z

166

Crown Ethers Flatten in Graphene for Strong, Specific Binding...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

SHARE Crown Ethers Flatten in Graphene for Strong, Specific Binding ORNL discovery holds potential for separations, sensors, batteries, biotech and more This sheet of graphene...

167

E-Print Network 3.0 - aqueous crown ethers Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ether recognition agent, as well as a glucose sensor, which utilizes... -3760, USA. vinyl crown ether into the PCCA 1,5-8. In contrast, we fab- ricatedaglucosesensing......

168

Process for producing dimethyl ether form synthesis gas  

DOE Patents [OSTI]

This invention pertains to a Fischer Tropsch process for converting synthesis gas to an oxygenated hydrocarbon with particular emphasis on dimethyl ether. Synthesis gas comprising carbon monoxide and hydrogen are converted to dimethyl ether by carrying out the reaction in the presence of an alkali metal-manganese-iron carbonyl cluster incorporated onto a zirconia-alumina support.

Pierantozzi, Ronald (Macungie, PA)

1985-01-01T23:59:59.000Z

169

anhydride-methyl vinyl ether: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Low Band Gap Polymers" Weibin Cui and Fred Wudl Macromolecules, 46 (18): 7232-7238 (2013). DOI Link "A Montarnal, Nancy D. Eisenmenger, Sung-Yu Ku, Michael L....

170

acid-methyl vinyl ether: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Low Band Gap Polymers" Weibin Cui and Fred Wudl Macromolecules, 46 (18): 7232-7238 (2013). DOI Link "A Montarnal, Nancy D. Eisenmenger, Sung-Yu Ku, Michael L....

171

Biodegradation of methyl tertiary butyl ether (MTBE) using a granular activated carbon trickling filter  

SciTech Connect (OSTI)

A pilot scale trickling filter was constructed using granular activated carbon (GAC) as the packing medium and inoculated with a microbial culture known to degrade MTBE. The packing dimensions were 0.076 m in diameter and 0.22 m deep. The unit operated with recycling flow for two months before a biofilm was observed on the GAC. After two additional months the biofilm had visibly spread throughout the packing. A few pieces of GAC were placed in a sealed bottle with MTBE-contaminated water and nutrients. Headspace analysis performed over 14 days confirmed that MTBE degradation was occurring. The trickling filter was converted to continuous flow and operated for one month at a nominal flow rate of 0.1 L/min and a hydraulic loading rate of 32 m{sup 3}/m{sup 2}-d. Samples were collected for analysis at the spray nozzle and at the bottom of the trickling filter. Fractional removal varied with influent MTBE concentration, temperature and liquid flow rate. Percent MTBE removal was as high as 85%. A mechanical failure resulted in the trickling filter bed drying and percent removal dropping to less than 1 percent. However, the system recovered within five days.

Converse, B.M.; Schroeder, E.D.; Chang, D.P.Y.

1999-07-01T23:59:59.000Z

172

Synergistic effect of mixing dimethyl ether with methane, ethane, propane, and ethylene fuels on polycyclic aromatic hydrocarbon and soot formation  

SciTech Connect (OSTI)

Characteristics of polycyclic aromatic hydrocarbon (PAH) and soot formation in counterflow diffusion flames of methane, ethane, propane, and ethylene fuels mixed with dimethyl ether (DME) have been investigated. Planar laser-induced incandescence and fluorescence techniques were employed to measure relative soot volume fractions and PAH concentrations, respectively. Results showed that even though DME is known to be a clean fuel in terms of soot formation, DME mixture with ethylene fuel increases PAH and soot formation significantly as compared to the pure ethylene case, while the mixture of DME with methane, ethane, and propane decreases PAH and soot formation. Numerical calculations adopting a detailed kinetics showed that DME can be decomposed to produce a relatively large number of methyl radicals in the low-temperature region where PAH forms and grows; thus the mixture of DME with ethylene increases CH{sub 3} radicals significantly in the PAH formation region. Considering that the increase in the concentration of O radicals is minimal in the PAH formation region with DME mixture, the enhancement of PAH and soot formation in the mixture flames of DME and ethylene can be explained based on the role of methyl radicals in PAH and soot formation. Methyl radicals can increase the concentration of propargyls, which could enhance incipient benzene ring formation through the propargyl recombination reaction and subsequent PAH growth. Thus, the result substantiates the importance of methyl radicals in PAH and soot formation, especially in the PAH formation region of diffusion flames. (author)

Yoon, S.S. [Corporate Research and Development Division, Hyundai-Kia Motors, Gyeonggi-do 445-706 (Korea); Anh, D.H. [Korea Electric Power Research Institute, Daejeon 305-380 (Korea); Chung, S.H. [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742 (Korea)

2008-08-15T23:59:59.000Z

173

Origin of mechanical modifications in poly (ether ether ketone)/carbon nanotube composite  

SciTech Connect (OSTI)

Variations in the hardness of a poly (ether ether ketone) beam electrically modified with multi-walled carbon nanotubes (MWCNT, 0.5%-3%) are investigated. It is shown that both rupture and hardness variations correlate with the changes in carbon nanotube concentration when using micro indentation and extended Raman imaging. Statistical analysis of the relative spectral intensities in the Raman image is used to estimate local tube concentration and polymer crystallinity. We show that the histogram of the Raman D band across the image provides information about the amount of MWCNTs and the dispersion of MWCNTs in the composite. We speculate that we have observed a local modification of the ordering between pure and modified polymer. This is partially supported by small angle neutron scattering measurements, which indicate that the agglomeration state of the MWCNTs is the same at the concentrations studied.

Pavlenko, Ekaterina; Puech, Pascal; Bacsa, Wolfgang, E-mail: wolfgang.bacsa@cemes.fr [CEMES-CNRS and University of Toulouse, 29 Jeanne Marvig, 31055 Toulouse (France); Boyer, François; Olivier, Philippe [Université de Toulouse, Institut Clément Ader, I.U.T. Université Paul Sabatier - 133C Avenue de Rangueil - B.P. 67701, 31077 Toulouse CEDEX 4 (France); Sapelkin, Andrei [School of Physics and Astronomy, Queen Mary, University of London, Mile End Road, E1 4NS London (United Kingdom); King, Stephen; Heenan, Richard [ISIS Facility, Rutherford Appleton Laboratory, Chilton, OX11 0QX Didcot (United Kingdom); Pons, François; Gauthier, Bénédicte; Cadaux, Pierre-Henri [AIRBUS FRANCE (B.E. M and P Toulouse), 316 Route de Bayonne, 31060 Toulouse (France)

2014-06-21T23:59:59.000Z

174

Crown Ethers in Nonaqueous Electrolytes for Lithium/Air Batteries  

SciTech Connect (OSTI)

The effects of three crown ethers, 12-crown-4, 15-crown-5, and 18-crown-6, as additives and co-solvents in non-aqueous electrolytes on the cell performance of primary Li/air batteries operated in a dry air environment were investigated. Crown ethers have large effects on the discharge performance of non-aqueous electrolytes in Li/air batteries. A small amount (normally less than 10% by weight or volume in electrolytes) of 12-Crown-4 and 15-crown-5 reduces the battery performance and a minimum discharge capacity appears at the crown ether content of ca. 5% in the electrolytes. However, when the content increases to about 15%, both crown ethers improve the capacity of Li/air cells by about 28% and 16%, respectively. 15-Crown-5 based electrolytes even show a maximum discharge capacity in the crown ether content range from 10% to 15%. On the other hand, the increase of 18-crown-6 amount in the electrolytes continuously lowers of the cell performance. The different battery performances of these three crown ethers in electrolytes are explained by the combined effects from the electrolytes’ contact angle, oxygen solubility, viscosity, ionic conductivity, and the stability of complexes formed between crown ether molecules and lithium ions.

Xu, Wu; Xiao, Jie; Wang, Deyu; Zhang, Jian; Zhang, Jiguang

2010-02-04T23:59:59.000Z

175

Molecular Mechanism of Polybrominated Diphenyl Ether Disposition in the Liver  

E-Print Network [OSTI]

Polybrominated diphenyl ethers (PBDEs) were introduced in the late 1970's as additive flame retardants incorporated into textiles, electronics, plastics and furniture. Although 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ...

Pacyniak, Erik Kristofer

2010-10-01T23:59:59.000Z

176

A review of the environmental behavior and fate of fuel oxygenates  

SciTech Connect (OSTI)

The ways in which fuel oxygenate compounds behave in water, soil, and air are determined by how they partition among the different media. The behavior of a gasoline oxygenate in water is affected by the oxygenate`s (1) solubility in water from gasoline: (2) partitioning between water and soil materials; and (3) partitioning between air and water. Water in equilibrium with oxygenated gasoline can contain high concentrations of the oxygenate. For example, at room temperature water solubility of methyl tert-butyl ether (MTBE) will be about 5,000 mg/L for a gasoline that is 10% MTBE by weight. In contrast, the total hydrocarbon solubility in water is typically about 120 mg/L for nonoxygenated gasoline. Fuel oxygenates sorb only weakly to soil and aquifer materials. Therefore, sorption to these materials will not significantly retard their transport by ground water. Fuel oxygenates tend to partition into atmospheric water, including precipitation. For example, washout of gas-phase MTBE by precipitation would not, by itself, greatly alter the gas-phase concentration of the compound in the atmosphere. Nevertheless, the partitioning of MTBE to precipitation is strong enough to allow for submicrogram per liter to 3 pg/L or more inputs of MTBE to ground water and surface water. Occurrence data for MTBE in water and air supports partition theoretical calculations. MTBE and other alkyl ether oxygenates have half lives in the atmosphere that range from about 1 to 14 days. These compounds are generally considered recalcitrant in ground water; whereas ethanol and methanol will readily undergo microbial degradation except where present in concentrations toxic to microorganisms.

Squillace, P.J.

1995-12-31T23:59:59.000Z

177

Directed metalation of N,N-diethylbenzamides. Silylated benzamides for the synthesis of naturally occurring peri-methylanthraquinones and peri-methyl polycyclic aromatic hydrocarbons  

SciTech Connect (OSTI)

Efficient methodologies based on directed ortho metalation, fluoride-induced carbodesilylation, and metal-halogen exchange processes (Scheme I) are reported for the synthesis of peri-methyl-substituted anthraquinone natural products 5 and polycyclic aromatic hydrocarbons 6, 7. Benzamide 8 (Scheme II) is converted in a one-pot sequence into the disilylated derivative 10, which upon metalation, condensation with 3,5-dimethoxybenzaldehyde, CsF desilylation, and TsOH cyclization leads to the key phthalide 11. Compound 11 is transformed into deoxyerythrolaccin tris(methyl ether) 5c, which has been previously converted into the natural product 5a. For the synthesis of erythrolaccin tetrakis(methyl ether) 5d, the silyl and bromo benzamides 14 and 15 (Scheme III) are condensed with 3,5-dimethoxybenzaldehyde by CsF-induced carbodesilylation and metal-halogen exchange expedients, respectively, to give the phthalide 16, which is transformed into the target anthraquinone 55d by methods identical with those used in 5c. Along similar lines, the synthesis of 11-methyl-7,12-benz(a)anthraquinone (6a, Scheme IV), 8-methyl-7,12-benz(a)anthraquinone (6b), and 10-methyl-9,14-dibenz(a,c)anthraquinone (7) is described.

Mills, R.J.; Snieckus, V. (Univ. of Waterloo, Ontario (Canada))

1989-09-01T23:59:59.000Z

178

Comparative Environmental Performance of Two-Diesel-Fuel Oxygenates: Dibutyl Maleate (DBM) and Triproplyene Glycol Monomethyl Ether (TGME)  

SciTech Connect (OSTI)

Many studies have shown that the addition of oxygen bearing compounds to diesel fuel can significantly reduce particulate emissions. To assist in the evaluation of the environmental performance of diesel-fuel oxygenates, we have implemented a suite of diagnostic models for simulating the transport of compounds released to air, water, and soils/groundwater as well as regional landscapes. As a means of studying the comparative performance of DBM and TGME, we conducted a series of simulations for selected environmental media. Benzene and methyl tertiary butyl ether (MTBE) were also addressed because they represent benchmark fuel-related compounds that have been the subject of extensive environmental measurements and modeling. The simulations showed that DBM and TGME are less mobile in soil because of reduced vapor-phase transport and increased retention on soil particles. The key distinction between these two oxygenates is that DBM is predicted to have a greater potential than TGME for aerobic biodegradation, based on chemical structure.

Layton, D.W.; Marchetti, A.A.

2001-10-01T23:59:59.000Z

179

Experimental study and chemical analysis of n-heptane homogeneous charge compression ignition combustion with port injection of reaction inhibitors  

SciTech Connect (OSTI)

The control of ignition timing in the homogeneous charge compression ignition (HCCI) of n-heptane by port injection of reaction inhibitors was studied in a single-cylinder engine. Four suppression additives, methanol, ethanol, isopropanol, and methyl tert-butyl ether (MTBE), were used in the experiments. The effectiveness of inhibition of HCCI combustion with various additives was compared under the same equivalence ratio of total fuel and partial equivalence ratio of n-heptane. The experimental results show that the suppression effectiveness increases in the order MTBE < isopropanol << ethanol < methanol. But ethanol is the best additive when the operating ranges, indicated thermal efficiency, and emissions are considered. For ethanol/n-heptane HCCI combustion, partial combustion may be observed when the mole ratio of ethanol to that of total fuel is larger than 0.20; misfires occur when the mole ratio of ethanol to that of total fuel larger than 0.25. Moreover, CO emissions strongly depend on the maximum combustion temperature, while HC emissions are mainly dominated by the mole ratio of ethanol to that of total fuel. To obtain chemical mechanistic informations relevant to the ignition behavior, detailed chemical kinetic analysis was conducted. The simulated results also confirmed the retarding of the ignition timing by ethanol addition. In addition, it can be found from the simulation that HCHO, CO, and C{sub 2}H{sub 5}OH could not be oxidized completely and are maintained at high levels if the partial combustion or misfire occurs (for example, for leaner fuel/air mixture). (author)

Lue, Xingcai; Ji, Libin; Zu, Linlin; Hou, Yuchun; Huang, Cheng; Huang, Zhen [School of Mechanical and Power Engineering, Shanghai Jiaotong University, Shanghai (China)

2007-05-15T23:59:59.000Z

180

Numerical study of the effect of oxygenated blending compounds on soot formation in shock tubes  

SciTech Connect (OSTI)

This numerical study deals with the influence of blends on the amount of soot formed in shock tubes, which were simulated by assuming a homogeneous plug flow reactor model. For this purpose, first, the reaction model used here was validated against experimental results previously obtained in the literature. Then, the soot volume fractions of various mixtures of methyl tert-butyl ether (MTBE)-benzene, isobutene-benzene, methanol-benzene, and ethanol-benzene diluted in argon were simulated and compared to the results of benzene-argon pyrolysis at 1721 K and 5.4 MPa. For MTBE, isobutene, methanol, and ethanol, small amounts of additives to benzene-argon mixtures promoted soot formation, for the shock tube model assumed, while higher concentrations of these additives led to smaller soot volume fractions in comparison to pure benzene-argon pyrolysis. The most significant soot promotion effect was found for the additives MTBE and isobutene. The channel for MTBE decomposition producing isobutene and methanol is very effective at temperatures beyond 1200 K. Thus, both MTBE-benzene and isobutene-benzene mixtures diluted in argon showed rather similar behavior in regard to soot formation. Special emphasis was directed toward the causes for the concentration-dependent influence of the blends on the amount of soot formed. Aromatic hydrocarbons and acetylene were identified as key gas-phase species that determine the trends in the formation of soot of various mixtures. From reaction flux analysis for phenanthrene, it was deduced that the combinative routes including phenyl species play a major role in forming PAHs, especially at early reaction times. It is found that the additives play an important role in providing material to grow side chains, such as by reaction channels including phenylacetylene or benzyl, which are confirmed to form aromatic hydrocarbons and thus to influence the amount of soot formed, particularly when the concentrations of the blends are increased. (author)

Boehm, H. [Physikalische Chemie I, Universitaet Bielefeld (Germany); Braun-Unkhoff, M. [Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Stuttgart (Germany)

2008-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Iron optimization for Fenton-driven oxidation of MTBE-spent granular activated carbon  

SciTech Connect (OSTI)

Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was accomplished through the addition of iron (Fe) and hydrogen peroxide (H{sub 2}O{sub 2}) (15.9 g/L; pH 3). The GAC used was URV, a bituminous-coal based carbon. The Fe concentration in GAC was incrementally varied (1020-25 660 mg/kg) by the addition of increasing concentrations of Fe solution (FeSO4{center_dot}7H{sub 2}O). MTBE degradation in Fe-amended GAC increased by an order of magnitude over Fe-unamended GAC and H{sub 2}O{sub 2} reaction was predominantly (99%) attributed to GAC-bound Fe within the porous structure of the GAC. Imaging and microanalysis of GAC particles indicated limited penetration of Fe into GAC. The optimal Fe concentration was 6710 mg/kg (1020 mg/kg background; 5690 mg/kg amended Fe) and resulted in the greatest MTBE removal and maximum Fe loading oxidation efficiency (MTBE oxidized (g)/Fe loaded to GAC(mg/Kg)). At lower Fe concentrations, the H{sub 2}O{sub 2} reaction was Fe limited. At higher Fe concentrations, the H{sub 2}O{sub 2} reaction was not entirely Fe limited, and reductions in GAC surface area, GAC pore volume, MTBE adsorption, and Fe loading oxidation efficiency were measured. Results are consistent with nonuniform distribution of Fe, pore blockage in H{sub 2}O{sub 2} transport, unavailable Fe, and limitations in H{sub 2}O{sub 2} diffusive transport, and emphasize the importance of optimal Fe loading. 22 refs., 6 figs., 2 tabs.

Scott G. Huling; Patrick K. Jones; Tony R. Lee [U.S. Environmental Protection Agency, Ada, OK (United States). Office of Research and Development, National Risk Management Research Laboratory

2007-06-01T23:59:59.000Z

182

Remediation of overlapping benzene/MTBE and MTBE-only plumes: A case study  

SciTech Connect (OSTI)

Two overlapping dissolved hydrocarbon plumes were identified in the shallow water-bearing zone at a commercial vehicle service and fueling facility. Plume 1 originated from a pre-1993 gasoline product line/dispenser leak. This plume contained a relatively common mix of benzene, toluene, ethylbenzene, xylenes (BTEX), and methyl tert-butyl ether (MTBE); benzene and MTBE were identified as the Plume 1 contaminants of concern based on their detection at approximately 200 {mu}g/l each, which exceeded regulatory guidance. Plume 2, which was detected in the tank cavity during UST removal, resulted from gasoline line leaks/underground storage tank overfills. Although the majority of impacted soils in both the dispenser and tank cavity areas were removed during UST excavation, rainfall during impacted soil removal mobilized the MTBE contained in the soils to groundwater. As a result, Plume 2 contained approximately 900 {mu}g/l MTBE while BTEX compounds were non-detect. Although the impacted zone sustained an approximate yield of only 0.3 gallon per minute, Pennsylvania regulations dictate that this zone must be treated as an aquifer. The failure of remediating gasoline plumes using pump-and-treat has been predominantly due to BTEX`s tendency to adsorb onto soil, creating a residual-phase product layer which acts as a continuing source of dissolved-phase BTEX. Based on this experience, most groundwater and remediation professionals reject pump-and-treat as a viable remedial option, except in situations where controlling groundwater movement is the predominant goal.

Carpenter, P.L. [TolTest, Inc., Pittsburgh, PA (United States); Vinch, C.A. [Ryder Transportation Services, Lawrenceville, NJ (United States)

1997-12-31T23:59:59.000Z

183

Detections of MTBE in surficial and bedrock aquifers in New England  

SciTech Connect (OSTI)

The gasoline additive methyl tert-butyl ether (MTBE) was detected in 24% of water samples collected from surficial and bedrock aquifers in areas of New England. MTBE was the most frequently detected volatile organic compound among the 60 volatile chemicals analyzed and was present in 33 of 133 wells sampled from July 1993 through September 1995. The median MTBE concentration measured in ground-water samples was 0.45 microgram per liter and concentrations ranged from 0.2 to 5.8 microgram per liter. The network of wells sampled for MTBE consisted of 103 monitoring wells screened in surficial sand-and-gravel aquifers and 30 domestic-supply wells in fractured crystalline bedrock aquifers. Seventy-seven percent of all MTBE detections were from 26 shallow monitoring wells screened in surficial aquifers. MTBE was detected in42% of monitoring wells in urban areas. In agricultural areas, MTBE was detected i 8% (2 of 24) of wells and was not detected in undeveloped areas. Sixty-two percent of the MTBE detections in surficial aquifers were from wells within 0.25 mile of gasoline stations or underground gasoline storage tanks; all but one of these wells were in Connecticut and Massachusetts, where reformulated gasoline is used. MTBE was detected in 23% of deep domestic-supply wells that tapped fractured bedrock aquifers. MTBE was detected in bedrock wells only in Connecticut and Massachusetts; land use near the wells was suburban to rural, and none of the sampled bedrock wells were within 0.25 mile of a gasoline station.

Grady, S.J. [Geological Survey, Hartford, CT (United States)

1995-12-31T23:59:59.000Z

184

Remediation of a fractured clay soil contaminated with gasoline containing MTBE  

SciTech Connect (OSTI)

Gasoline and other light non-aqueous phase liquids (LNAPLs) released into fractured clay soils initially move by advection of the LNAPL through the fractures. Once advective movement of the LNAPL ceases, dissolution of the gasoline components into the pore water and diffusion into the intact blocks of clay becomes an important transport process. The aqueous-phase flux of each compound in the mixture depends in large part upon its aqueous solubility. For example, a low-solubility compound like isooctane remains primarily in the fracture in the LNAPL. A high-solubility compound, like methyl-tert-butyl ether (MTBE), dissolves readily and may move almost entirely into the clay matrix. The distribution of compounds between the matrix and the fractures will have an important impact on the rate at which the gasoline contaminated soil can be remediated. In this context, the presence of soluble additives like MTBE can significantly impact the risk and remediation time for the, soil. Beginning in 1993 a field study to examine the applicability of air flushing for remediation of low-permeability soils was sponsored by API. The study focused on a variety of soil vapor extraction (SVE) and in situ air sparging (IAS) approaches for mass removal and risk reduction. The source of gasoline contamination in this study was a release of 50 liters of a mixture containing 14 gasoline hydrocarbons ranging from pentane to naphthalene, and including MTBE. The mixture was released into the shallow subsurface and allowed to redistribute for 10 months prior to air flushing startup. Numerical modeling indicated that essentially all of the MTBE should have dissolved into the matrix. In contrast, essentially all of the isooctane should have remained in the LNAPL in the fractures.

Johnson, R.L.; Grady, D.E. [Oregon Graduate Institute, Portland, OR (United States); Walden, T. [BP Oil Europe, Brussels (Belgium)

1997-12-31T23:59:59.000Z

185

Center for Water Resources Annual Technical Report  

E-Print Network [OSTI]

of Ethanol on Anaerobic Production of Tert-Butyl Alcohol (TBA) from MTBE in Groundwater Kate M. Scow, Douglas

186

The interactions of water and perfluorodiethyl ether on Ru(100)  

SciTech Connect (OSTI)

We have studied the interactions of water and perfluorodiethyl ether on Ru(100) in order to model the effects of surface structure and humidity on the bonding and decomposition of perfluoroalkyl ether lubricants with metal surfaces. In order to understand the interactions on Ru(100), we have first investigated the interactions of each of these adsorbates alone on the clean surface. The interactions of water with Ru(100) have been studied using both thermal desorption spectroscopy (TDS) and electron energy loss spectroscopy (EELS). From these studies we conclude that a small amount of water dissociates on this surface (5--10% of a monolayer), but water is adsorbed in a predominantly molecular form on this surface with an increasing degree of hydrogen-bonding with increasing coverage. The effects of hydrogen and oxygen coadsorption on the interactions of water with this surface have also been studied using TDS. Finally, the interactions of coadsorbed water and perfluorodiethyl ether on Ru(100) have been investigated using TDS.

Leavitt, P.

1990-09-21T23:59:59.000Z

187

Detailed chemical kinetic reaction mechanism for biodiesel components methyl stearate and methyl oleate  

E-Print Network [OSTI]

Detailed chemical kinetic reaction mechanism for biodiesel components methyl stearate and methyl are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate renewable sources, can reduce net emissions of greenhouse gases. An important class of biodiesel fuels

Paris-Sud XI, Université de

188

E-Print Network 3.0 - aromatic crown ethers Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

cryptands are unique macrocycles. Since Lehn's seminal... that are several orders of magnitude greater than monomacrocyclic crown ethers.7 Size recognition properties......

189

E-Print Network 3.0 - allyl glycidyl ether Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Science 15 () Trichloromethane ()1,1,2,2-1,1,2,2-Tetrachloroethane Summary: ;() Acrolein () Acrylic acid () Allyl zlcohol () Allyl chloride () Allyl glycidyl ether(AGE) ()2-...

190

E-Print Network 3.0 - anesthesia ether cyclopropane Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2 cm Source: Ecole Polytechnique, Centre de mathmatiques Collection: Mathematics 70 An Electrochemical Approach to the Guanacastepenes Summary: ), and the resulting enol ether...

191

E-Print Network 3.0 - anticancer ether lipid Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Butyric acid Oligosaccharides Peptides 13-methyltetradecanoic acid Nucleosides Ether lipids... led to a substantial increase in our knowledge of the intracellular origin of...

192

POLYCHLORINATED BIPHENYLS AND POLYBROMINATED DIPHENYL ETHERS IN GALAPAGOS SEA LIONS (ZALOPHUS WOLLEBAEKI)  

E-Print Network [OSTI]

), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p- dioxins (PCDDs), and polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) repre- sent persistent

Gobas, Frank

193

E-Print Network 3.0 - alpha -chloro ethers Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

YU, and JEONG S. YU, Department of Chemistry and Chemical... functions of two engineering plastics a poly(phenylene ether) and a polycether imide) were characterized...

194

Methyl tertiary butyl ether (MtBE) contamination of the City of Santa Monica drinking water supply  

SciTech Connect (OSTI)

In the summer of 1996, the City of Santa Monica ceased pumping groundwater from two Well Fields (Charnock and Arcadia) used for public drinking water supply due to persistent and increasing concentrations of MtBE in all seven municipal water supply wells. This lost production accounted for 50% of the City`s total drinking water supply. In late 1996, the City, in cooperation with State and Federal agencies, initiated an investigation of MtBE contamination at the two well fields. The objectives of the investigation were as follows: (1) Review available data on the production, use, chemical characteristics, fate and transport, toxicology, and remediation of MtBE; (2) Identify locations of potential sources of MtBE groundwater contamination at the well fields; (3) Develop an understanding of the hydrologic pathways from the potential sources to the drinking water wells; and (4) Evaluate alternative treatment technologies for the removal of MtBE from drinking water. In addition to a review of available information about MtBE, the investigation included an extensive review of literature and available data relevant to the well fields, including well field production histories, site and regional hydrogeology, all well logs and production in the groundwater basins, general groundwater quality, and the record of MtBE detection. Based upon the review of background information, conceptual hydrogeologic models were developed. A detailed review of agency files for over 45 potential source sites was conducted. The information from this review was summarized, and source site screening and ranking criteria were developed. A field program was conducted at the major well field (Charnock), including soil gas surveys, CPTs, soil borings and well installations, geophysics, and aquifer testing. The field program provided site data which allowed the conceptual hydrogeologic model to be refitted to actual site conditions.

Brown, A.; Farrow, J.R.C. [Komex H2O Science, Huntington Beach, CA (United States); Rodriguez, R.A. [City of Santa Monica, CA (United States)] [and others

1997-12-31T23:59:59.000Z

195

Review of potential technologies for the treatment of Methyl tertiary butyl Ether (MtBE) in drinking water  

SciTech Connect (OSTI)

At present, the state of knowledge on effective treatment technologies for MtBE in drinking water, and groundwater in general, is limited. Research by others is focusing on the remediation of MtBE close to the point of release. The City of Santa Monica, MWD, Komex and USC are currently conducting research into different technologies that could be used to remove MtBE from drinking water supplies. The objectives of the research are to evaluate different treatment technologies to identify cost-effective and technically feasible alternatives for the removal of MtBE from drinking water. The evaluation is considering moderate to high water flow rates (100 to 2,000+ gpm) and low to moderate MtBE concentrations (<2,000 {mu}g/l). The research program includes four phases: (1) Literature Review; (2) Bench Scale Study; (3) Field Scale Pre-pilot Study; and (4) Summary Evaluation. This paper presents some preliminary information and findings from the first phase of this research - the literature review. The review discusses the chemical properties of MtBE and how they affect remediation and thus, an evaluation of alternative treatment technologies. The review of available literature, and the applicability and limitations of the following technologies are presented in detail.

Brown, A.; Browne, T.E. [Komex H2O Science, Huntington Beach, CA (United States); Devinny, J.S. [Univ. of Southern California, Los Angeles, CA (United States)] [and others

1997-12-31T23:59:59.000Z

196

Polybrominated diphenyl ether flame retardants in the antarctic environment  

E-Print Network [OSTI]

, the historical record of dioxins, PCBs and DDTs in the same cores showed a decreasing trend. At present, PBDEs are recognized as a worldwide pollution problem since they have reached remote areas such as the deep ocean, the Arctic and Antarctica (de Boer et al... that cheerful and warm Brazilian spirit. You are my Aggie family! viii NOMENCLATURE #1; critical value of a statistical test used to reject the null hypothesis ANOVA Analysis of Variance BDE Brominated Diphenyl Ether BFR Brominated Flame Retardant DC...

Yogui, Gilvan Takeshi

2009-05-15T23:59:59.000Z

197

Proton-conducting polymer electrolyte membranes based on fluoropolymers incorporating perfluorovinyl ether sulfonic acids and fluoroalkenes  

E-Print Network [OSTI]

acids. A novel synthetic route describing the preparation of perfluorovinyl ether monomer containing. The radical (co) and terpolymerization of 4-[(,,-trifluorovinyl)oxy]benzene sulfonyl chloride (TFVOBSC) with 1,1-difluoroethylene (or vinylidene fluoride, VDF), hexafluoropropene (HFP), and perfluoromethyl vinyl ether (PMVE

Paris-Sud XI, Université de

198

Decomposition of Ethanol and Dimethyl Ether During Chemical Vapour deposition Synthesis  

E-Print Network [OSTI]

1 Decomposition of Ethanol and Dimethyl Ether During Chemical Vapour deposition Synthesis of Single-phase thermal decomposition of ethanol and dimethyl ether (DME) at typical SWNT growth conditions using to the predicted decomposition mechanism. Signature peak intensities indicated concentrations of both ethanol

Maruyama, Shigeo

199

[sup 7]Li-NMR determination of stability constants as a function of temperature for lithium-crown ether complexes in a molten salt mixtures  

SciTech Connect (OSTI)

The stability constants of several crown ethers with lithium ion were determined by [sup 7]Li-NMR measurements. A room temperature, basic molten salt of the composition of 55/45 mol % 1-methyl-3-ethyl-imidazolium chloride to aluminum (III) chloride was used as solvent. On the basis of a 1:1 complex formation the following order was found for the stability constants of the investigated crown ethers: 18-crown-6 < 12-crown-4 < benzo-15-crown-5 < 15-crown-5. A temperature dependence study for 12-crown-4, benzo-15-crown-5, and 15-crown-5 was undertaken for the range 5-84[degree]C. Values of [Delta]H and [Delta]S were calculated. At 5.5[degree]C the splitting of the single, fast exchange peak into two separate signals was observed for benzo-15-crown-5, providing further evidence for the formation of the 1:1 complex. 34 refs., 4 figs., 5 tabs.

Gerhard, A. (Univ. of Utah, Salt Lake City, UT (United States) Univ. of Witten/Herdecke (Germany)); Cobranchi, D.P.; Garland, B.A.; Highley, A.M.; Huang, Y.H.; Konya, G.; Eyring, E.M. (Univ. of Utah, Salt Lake City, UT (United States)); Zahl, A.; Eldik, R. van (Univ. of Witten/Herdecke (Germany)); Petrucci, S. (Polytechnic Univ., Farmingdale, NY (United States))

1994-08-11T23:59:59.000Z

200

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOE Patents [OSTI]

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, D.; Waller, F.J.

1999-04-06T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOE Patents [OSTI]

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

1999-01-01T23:59:59.000Z

202

Use TAME and heavier ethers to improve gasoline properties  

SciTech Connect (OSTI)

Producing oxygenates from all potential FCC tertiary olefins is one of the most economic methods for reducing olefins and Reid vapor pressure (Rvp) in motor gasoline. MTBE production based on FCC isobutylene has reached a very high level. But the amount of MTBE from a refinery sidestream MTBE unit is insufficient for producing reformulated gasoline (RFG) and additional oxygenates must be purchased. The next phase will see conversion of isoamylenes in FCC light gasoline to TAME. Very little attention has been given to the heavier tertiary olefins present in the FCC light gasoline like tert-hexenes and heptenes. This route allows higher levels of oxygenates production, thereby lowering Rvp and the proportion of olefins in the gasoline pool and maximizing the use of FCC olefins. By using all the components produced by an FCC efficiently, many gasoline problems can be solved. Isobutene is converted to MTBE, C[sub 3]/C[sub 4] olefins are converted to alkylate and C[sub 5] tertiary olefins can be converted to TAME. All of these are preferred components for gasoline quality. By producing more oxygenates like MTBE, TAME and heavier ethers, a refinery can be self-sufficient in blending reformulated gasoline and no oxygenates need to be purchased. The technology for producing TAME and other ethers is described.

Ignatius, J.; Jaervelin, H.; Lindqvist, P. (Neste Engineering, Porvoo (Finland))

1995-02-01T23:59:59.000Z

203

Detailed Chemical Kinetic Reaction Mechanism for Biodiesel Components Methyl Stearate and Methyl Oleate  

SciTech Connect (OSTI)

New chemical kinetic reaction mechanisms are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate. The mechanisms are produced using existing reaction classes and rules for reaction rates, with additional reaction classes to describe other reactions unique to methyl ester species. Mechanism capabilities were examined by computing fuel/air autoignition delay times and comparing the results with more conventional hydrocarbon fuels for which experimental results are available. Additional comparisons were carried out with measured results taken from jet-stirred reactor experiments for rapeseed methyl ester fuels. In both sets of computational tests, methyl oleate was found to be slightly less reactive than methyl stearate, and an explanation of this observation is made showing that the double bond in methyl oleate inhibits certain low temperature chain branching reaction pathways important in methyl stearate. The resulting detailed chemical kinetic reaction mechanism includes more approximately 3500 chemical species and more than 17,000 chemical reactions.

Naik, C; Westbrook, C K; Herbinet, O; Pitz, W J; Mehl, M

2010-01-22T23:59:59.000Z

204

Single-Step Syngas-to-Distillates (S2D) Synthesis via Methanol and Dimethyl Ether Intermediates: Final Report  

SciTech Connect (OSTI)

The objective of the work was to enhance price-competitive, synthesis gas (syngas)-based production of transportation fuels that are directly compatible with the existing vehicle fleet (i.e., vehicles fueled by gasoline, diesel, jet fuel, etc.). To accomplish this, modifications to the traditional methanol-to-gasoline (MTG) process were investigated. In this study, we investigated direct conversion of syngas to distillates using methanol and dimethyl ether intermediates. For this application, a Pd/ZnO/Al2O3 (PdZnAl) catalyst previously developed for methanol steam reforming was evaluated. The PdZnAl catalyst was shown to be far superior to a conventional copper-based methanol catalyst when operated at relatively high temperatures (i.e., >300°C), which is necessary for MTG-type applications. Catalytic performance was evaluated through parametric studies. Process conditions such as temperature, pressure, gas-hour-space velocity, and syngas feed ratio (i.e., hydrogen:carbon monoxide) were investigated. PdZnAl catalyst formulation also was optimized to maximize conversion and selectivity to methanol and dimethyl ether while suppressing methane formation. Thus, a PdZn/Al2O3 catalyst optimized for methanol and dimethyl ether formation was developed through combined catalytic material and process parameter exploration. However, even after compositional optimization, a significant amount of undesirable carbon dioxide was produced (formed via the water-gas-shift reaction), and some degree of methane formation could not be completely avoided. Pd/ZnO/Al2O3 used in combination with ZSM-5 was investigated for direct syngas-to-distillates conversion. High conversion was achieved as thermodynamic constraints are alleviated when methanol and dimethyl are intermediates for hydrocarbon formation. When methanol and/or dimethyl ether are products formed separately, equilibrium restrictions occur. Thermodynamic relaxation also enables the use of lower operating pressures than what would be allowed for methanol synthesis alone. Aromatic-rich hydrocarbon liquid (C5+), containing a significant amount of methylated benzenes, was produced under these conditions. However, selectivity control to liquid hydrocarbons was difficult to achieve. Carbon dioxide and methane formation was problematic. Furthermore, saturation of the olefinic intermediates formed in the zeolite, and necessary for gasoline production, occurred over PdZnAl. Thus, yield to desirable hydrocarbon liquid product was limited. Evaluation of other oxygenate-producing catalysts could possibly lead to future advances. Potential exists with discovery of other types of catalysts that suppress carbon dioxide and light hydrocarbon formation. Comparative techno-economics for a single-step syngas-to-distillates process and a more conventional MTG-type process were investigated. Results suggest operating and capital cost savings could only modestly be achieved, given future improvements to catalyst performance. Sensitivity analysis indicated that increased single-pass yield to hydrocarbon liquid is a primary need for this process to achieve cost competiveness.

Dagle, Robert A.; Lebarbier, Vanessa MC; Lizarazo Adarme, Jair A.; King, David L.; Zhu, Yunhua; Gray, Michel J.; Jones, Susanne B.; Biddy, Mary J.; Hallen, Richard T.; Wang, Yong; White, James F.; Holladay, Johnathan E.; Palo, Daniel R.

2013-11-26T23:59:59.000Z

205

A potassium crown ether complex with dichloroaurate(I)  

E-Print Network [OSTI]

Acta Cryst. (2003). E59, m57±m58 DOI: 10.1107/S1600536803000813 Md. Alamgir Hossain et al. #15; [K(C 12 H 24 O 6 )][AuCl 2 ] m57 metal-organic papers Acta Crystallographica Section E Structure Reports Online ISSN 1600-5368 A potassium crown ether...-james@ku.edu Key indicators Single-crystal X-ray study T = 100 K Mean #27;(C±C) = 0.002 A Ê R factor = 0.017 wR factor = 0.047 Data-to-parameter ratio = 27.2 For details of how these key indicators were automatically derived from the article, see http...

Hossain, Alamgir; Powell, Douglas R.; Bowman-James, Kristin

2003-01-17T23:59:59.000Z

206

Solvent Effects on Cesium Complexation with Crown Ethers from Liquid to Supercritical Fluids  

SciTech Connect (OSTI)

Nuclear magnetic resonance (NMR) techniques were used to study crown ether-water interactions in solvents of low dielectric constants such as chloroform and carbon tetrachloride. Water forms a 1:1 complex with a number of crown ethers including 12-crown-4, 15-crown-5, 18-crown-6, dicyclohexano-18=crown-6, dicyclohexano-24-crown 8, and dibenzl-24-crown-8 in chloroform. Among these crown ethers, the 18-crown-6-H2 complex has the largest equilibrium constant (K=545) and 97% of the crown is complexed to water in chloroform. Addition of carbon tetrachloride to chloroform lowers the equilibrium constants of the crown-water complexes. The partition coefficients of crown ethers (D=crown in water/crown in solvent) between water and organic solvent also vary with solvent composition.

Chien M. Wai; Anne Rustenholtz; Shaofen Wang; Su-Chen Lee; Jamie Herman; Richard A. Porter

2004-03-15T23:59:59.000Z

207

E-Print Network 3.0 - acid-labile cholesterol-vinyl ether-peg...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Crystallization of Recombinant Crithidia fasciculata Tryparedoxin Summary: of 30% polyethylene glycol monomethyl ether (PEG MME) 2000, 0.1 M TrisHCl, pH 8.2, 1% dimethyl Source:...

208

Study of the peroxidation mechanism of diethyl ether (DEE) International Symposium on Loss Prvention  

E-Print Network [OSTI]

and in allylic and benzylic structures. In figure 23 are presented peroxidizable moieties in order of decreasing hazard. l.Ethers and acetals with a-hvdroaen H -i-o-

Paris-Sud XI, Université de

209

Vapor-liquid equilibria for methanol + tetraethylene glycol dimethyl ether  

SciTech Connect (OSTI)

Vapor-liquid equilibrium (P-T-x) for the methanol + tetraethylene glycol dimethyl ether binary system were obtained by the static method in the range of temperatures from 293.15 to 423.15 K at 10 K intervals. The modified vapor pressure apparatus used is described. The Kuczynsky method was used to calculate the liquid and vapor composition and the activity coefficients of methanol from the initial composition of the sample and the measured pressure and temperature. The results were correlated by the NRTL and UNIQUAC temperature dependent activity coefficient models. This system shows nearly ideal behavior at 323.15 K, but positive deviations from ideality at lower temperatures and negative deviations at higher temperatures are observed. The activity coefficients become more negative with the increase in temperature and mole fraction of methanol. The excess molar enthalpy using the Gibss-Helmholtz equation and the NRTL and UNIQUAC parameters were calculated at 303.15 K and compared with experimental data. This binary system shows promise as a working pair for high-temperature heat pump applications.

Esteve, X.; Chaudhari, S.K.; Coronas, A. [Univ. Rovira i Virgili, Tarragona (Spain). Dept. of Electrical and Mechanical Engineering

1995-11-01T23:59:59.000Z

210

Treatability studies of groundwater contaminated with bis(2-chloroethyl) ether  

SciTech Connect (OSTI)

The groundwater aquifer underneath a chemical manufacturing plant in Southeast Texas has been contaminated with the leachate from its landfill. There are 17 major chlorinated hydrocarbon contaminants found in the groundwater with concentrations ranging from 1 ppm to 1,200 ppm. An air-stripping unit followed by a thermal catalytic oxidation unit is currently operating on-site to remove all of the chlorinated compounds from the contaminated groundwater. One of the contaminants, bis(2-chloroethyl)ether (DCEE), has a fairly low Henry`s Law constant; therefore, a high air flow rate is employed in the stripping unit to improve the overall stripping efficiency. Nevertheless, the treated groundwater still contains a fair amount of DCEE. An UV-peroxidation reactor is set up to study its feasibility for oxidizing DCEE. The treatability data indicate that DCEE at a concentration of 200 ppm can be oxidized effectively in the presence of H{sub 2}O{sub 2} and the effective UV wavelengths lie between 200 and 280 nm. No noticeable reduction of the oxidation rate is observed at low temperature ({approximately} 11 C). Apparent oxidation rate equations of DCEE are determined and several process design parameters are discussed.

Huang, F.Y.C. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Mineral and Environmental Engineering] [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Mineral and Environmental Engineering; Li, K.Y.; Liu, C.C. [Lamar Univ., Beaumont, TX (United States). Dept. of Chemical Engineering] [Lamar Univ., Beaumont, TX (United States). Dept. of Chemical Engineering

1999-05-01T23:59:59.000Z

211

Isothermal vapor-liquid equilibria for 2-methyl-2-butanol + 2-methyl-1-butanol + 1-pentanol  

SciTech Connect (OSTI)

Vapor-liquid equilibria (VLE) for 2-methyl-2-butanol + 2-methyl-1-butanol and 2-methyl-2-butanol + 2-methyl-1-butanol + 1-pentanol have been measured at 373.15 K. The binary VLE results have been correlated by different liquid-phase activity coefficient models. The binary interaction parameters obtained from Wilson, NRTL, and UNIQUAC models in this and a previously study are used to predict the VLE data for the ternary system. Vapor-liquid equilibrium (VLE) data are necessary for the design of distillation processes.

Aucejo, A.; Burguet, M.C.; Monton, J.B.; Munoz, R.; Sanchotello, M.; Vazquez, M.I. (Univ. of Valencia (Spain). Dept. de Ingenieria Quimica)

1994-07-01T23:59:59.000Z

212

DIMETHYL ETHER (DME)-FUELED SHUTTLE BUS DEMONSTRATION PROJECT  

SciTech Connect (OSTI)

The objectives of this research and demonstration program are to convert a campus shuttle bus to operation on dimethyl ether, a potential ultra-clean alternative diesel fuel. To accomplish this objective, this project includes laboratory evaluation of a fuel conversion strategy, as well as, field demonstration of the DME-fueled shuttle bus. Since DME is a fuel with no lubricity (i.e., it does not possess the lubricating quality of diesel fuel), conventional fuel delivery and fuel injection systems are not compatible with dimethyl ether. Therefore, to operate a diesel engine on DME one must develop a fuel-tolerant injection system, or find a way to provide the necessary lubricity to the DME. In this project, they have chosen the latter strategy in order to achieve the objective with minimal need to modify the engine. Their strategy is to blend DME with diesel fuel, to obtain the necessary lubricity to protect the fuel injection system and to achieve low emissions. The bulk of the efforts over the past year were focused on the conversion of the campus shuttle bus. This process, started in August 2001, took until April 2002 to complete. The process culminated in an event to celebrate the launching of the shuttle bus on DME-diesel operation on April 19, 2002. The design of the system on the shuttle bus was patterned after the system developed in the engine laboratory, but also was subjected to a rigorous failure modes effects analysis (FMEA, referred to by Air Products as a ''HAZOP'' analysis) with help from Dr. James Hansel of Air Products. The result of this FMEA was the addition of layers of redundancy and over-pressure protection to the system on the shuttle bus. The system became operational in February 2002. Preliminary emissions tests and basic operation of the shuttle bus took place at the Pennsylvania Transportation Institute's test track facility near the University Park airport. After modification and optimization of the system on the bus, operation on the campus shuttle route began in early June 2002. However, the work and challenges continued as it has been difficult to maintain operability of the shuttle bus due to fuel and component difficulties. In late June 2002, the pump head itself developed operational problems (loss of smooth function) leading to excessive stress on the magnetic coupling and excessive current draw to operate. A new pump head was installed on the system to alleviate this problem and the shuttle bus operated successfully on DME blends from 10-25 vol% on the shuttle bus loop until September 30, 2002. During the period of operation on the campus loop, the bus was pulled from service, operated at the PTI test track and real-time emissions measurements were obtained using an on-board emissions analyzer from Clean Air Technologies International, Inc. Particulate emissions reductions of 60% and 80% were observed at DME blend ratios of 12 vol.% and 25 vol.%, respectively, as the bus was operated over the Orange County driving cycle. Increases in NOx, CO and HC emissions were observed, however. In summary, the conversion of the shuttle bus was successfully accomplished, particulate emissions reductions were observed, but there were operational challenges in the field. Nonetheless, they were able to demonstrate reliable operation of the shuttle bus on DME-diesel blends.

Elana M. Chapman; Shirish Bhide; Jennifer Stefanik; Howard Glunt; Andre L. Boehman; Allen Homan; David Klinikowski

2003-04-01T23:59:59.000Z

213

Fused ring and linking groups effect on overcharge protection for lithium-ion batteries.  

SciTech Connect (OSTI)

The derivatives of 1,3-benzodioxan (DBBD1) and 1,4-benzodioxan (DBBD2) bearing two tert-butyl groups have been synthesized as new redox shuttle additives for overcharge protection of lithium-ion batteries. Both compounds exhibit a reversible redox wave over 4 V vs Li/Li{sup +} with better solubility in a commercial electrolyte (1.2 M LiPF{sub 6}) dissolved in ethylene carbonate/ethyl methyl carbonate (EC/EMC 3/7) than the di-tert-butyl-substituted 1,4-dimethoxybenzene (DDB). The electrochemical stability of DBBD1 and DBBD2 was tested under charge/discharge cycles with 100% overcharge at each cycle in MCMB/LiFePO{sub 4} and Li{sub 4}Ti{sub 5}O{sub 12}/LiFePO{sub 4} cells. DBBD2 shows significantly better performance than DBBD1 for both cell chemistries. The structural difference and reaction energies for decomposition have been studied by density functional calculations.

Weng, W.; Zhang, Z.; Redfern, P. C.; Curtiss, L. A.; Amine, K.

2011-02-01T23:59:59.000Z

214

The Effect of the Di-Tertiary Butyl Peroxide (DTBP) additive on HCCI Combustion of Fuel Blends of Ethanol and Diethyl Ether  

E-Print Network [OSTI]

diethyl ether (DEE) in ethanol fuel blends for a range ofbio-derived fuel components (ethanol) in emission productsHCCI Combustion of Fuel Blends of Ethanol and Diethyl Ether

Mack, John Hunter; Buchholz, Bruce A; Flowers, Daniel L; Dibble, Robert W

2005-01-01T23:59:59.000Z

215

Ab initio calculations of various protonation sites in perfluorodiethyl ether: Models for high temperature lubricant decomposition?  

SciTech Connect (OSTI)

Although perfluoropolyether (PFPE) lubricants have found successful application in spacecraft mechanisms and computer hard drives, there eventual breakdown is irksome, and the mechanism of decomposition is the subject of much scrutiny. However, very little notice is taken of the monomer ethers on which the polymer lubricants are based. Recently, concerted studies of the Lewis base properties of various fluorinated ethers have been performed, both from an experimental and a theoretical viewpoint. As an extension of the theoretical work, this study presents ab initio theoretical consideration of the multiple potential basic sites within perfluorodiethyl ether, (CF{sub 3}CF{sub 2}){sub 2}O, by way of the proton affinity of the molecule at various possible protonation sites (i.e., oxygen and fluorine atoms). The results indicate that although protonation at the oxygen is more energetically favored, protonation at the fluorine is not much higher in energy and provides for formation of an excellent leaving group, HF.

Ball, D.W. [Cleveland State Univ., OH (United States). Dept. of Chemistry

1995-04-01T23:59:59.000Z

216

Catalyst system and process for benzyl ether fragmentation and coal liquefaction  

DOE Patents [OSTI]

Dibenzyl ether can be readily cleaved to form primarily benzaldehyde and toluene as products, along with minor amounts of bibenzyl and benzyl benzoate, in the presence of a catalyst system comprising a Group 6 metal, preferably molybdenum, a salt, and an organic halide. Although useful synthetically for the cleavage of benzyl ethers, this cleavage also represents a key model reaction for the liquefaction of coal; thus this catalyst system and process should be useful in coal liquefaction with the advantage of operating at significantly lower temperatures and pressures.

Zoeller, J.R.

1998-04-28T23:59:59.000Z

217

Toxicity of polychlorinated diphenyl ethers in Hydra attenuata and in rat whole embryo culture  

E-Print Network [OSTI]

TOXICITY OF POLYCHLORINATED DIPHENYL ETHERS IN HYDRA A?TENUATA AND IN RAT WHOLE EMBRYO CULTURE A Thesis by MARION CAROL BECKER Submitted to the Office of Graduate Studies of Texas A8cM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 1991 Major Subject: Toxicology TOXICITY OF POLYCHLORINATED DIPHENYL ETHERS IN HYDRA A1TENUATA AND IN RAT WHOLE EMBRYO CULTURE by MARION CAROL BECKER Approved as to style and content by: Stephen H. S (Ca...

Becker, Marion Carol

1991-01-01T23:59:59.000Z

218

Determination of Total Lipids as Fatty Acid Methyl Esters (FAME...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

will be replaced by an ester bond between the fatty acid and a methyl group, producing methyl esters of the fatty acids (FAME) and free glycerol. 1.4 The FAME are then...

219

Comparative Dynamics of Leucine Methyl Groups in FMOC-Leucine...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Dynamics of Leucine Methyl Groups in FMOC-Leucine and in a ProteinHydrophobic Core Probed by Solid-State Deuteron Comparative Dynamics of Leucine Methyl Groups in FMOC-Leucine and...

220

Sub-millimeter sized methyl butanoate droplet combustion: Microgravity experiments  

E-Print Network [OSTI]

-dependent, sphero-symmetric droplet combustion simulation that includes detailed gas phase chemical kineticsSub-millimeter sized methyl butanoate droplet combustion: Microgravity experiments and detailed 2012 Abstract Combustion characteristics of isolated sub-millimeter sized methyl butanoate (MB

Walter, M.Todd

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Vapor-liquid equilibria for systems of 1-butanol with 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol at 30 and 100 kPa  

SciTech Connect (OSTI)

Vapor-liquid equilibrium data were measured for binary systems of 1-butanol with 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, and 3-methyl-2-butanol at 30 and 100 kPa. The experimental data obtained in this work are thermodynamically consistent according to a point-to-point consistency test, and deviation from ideal behavior is small in all cases. They can be equally well correlated with the Margules, Van Laar, Wilson, NRTL, and UNIQUAC equations.

Aucejo, A.; Burguet, M.C.; Monton, J.B.; Munoz, R.; Sanchotello, M.; Vazquez, M.I. (Univ. de Valencia (Spain). Dept. de Ingenieria Quimica)

1994-04-01T23:59:59.000Z

222

Lithium Hexamethyldisilazide-Mediated Ketone Enolization: The Influence of Hindered Dialkyl Ethers and Isostructural  

E-Print Network [OSTI]

Lithium Hexamethyldisilazide-Mediated Ketone Enolization: The Influence of Hindered Dialkyl Ethers of the enolization of 2-methylcyclohexanone mediated by lithium hexameth- yldisilazide (LiHMDS; TMS2NLi) solvated- bine to make lithium hexamethyldisilazide (LiHMDS) one of the most important Bro¨nsted bases in organic

Collum, David B.

223

Dimethyl ether (DME) from coal as a household cooking fuel in China  

E-Print Network [OSTI]

be made from any carbonaceous feedstock, including natural gas, coal, or biomass, using establishedDimethyl ether (DME) from coal as a household cooking fuel in China Eric D. Larson Princeton gas (LPG) as a household cooking fuel. As such, DME is an attractive fuel for clean cooking. DME can

224

Viscoelastic Behavior of Poly(ether imide) Incorporated with Multiwalled Carbon Nanotubes  

E-Print Network [OSTI]

plastic, and suitable for use in many demanding applications because of its relatively high strength, high, and thermal properties of engineering plastics, including poly(ether imide) (PEI), with various nanoin; viscoelastic properties INTRODUCTION The demand for lightweight materials with high strength and thermal

Fisher, Frank

225

E-Print Network 3.0 - amplified methylation polymorphism Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Environmental Sciences and Ecology 2 Infraspecific DNA Methylation Polymorphism in Cotton (Gossypium Summary: Infraspecific DNA Methylation Polymorphism in Cotton (Gossypium...

226

Middlesex FUSRAP Site - A Path to Site-Wide Closure - 13416  

SciTech Connect (OSTI)

The road-map to obtaining closure of the Middlesex Sampling Plant FUSRAP site in Middlesex, New Jersey (NJ) has required a multi-faceted approach, following the CERCLA Process. Since 1998, the US ACE, ECC, and other contractors have completed much of the work required for regulatory acceptance of site closure with unrestricted use. To date, three buildings have been decontaminated, demolished, and disposed of. Two interim storage piles have been removed and disposed of, followed by the additional removal and disposal of over 87,000 tons of radiologically and chemically-impacted subsurface soils by the summer of 2008. The US ACE received a determination from the EPA for the soils Operable Unit, (OU)-1, in September 2010 that the remedial excavations were acceptable, and meet the criteria for unrestricted use as required by the 2004 Record of Decision (ROD) for OU-1. Following the completion of OU-1, the project delivery team performed additional field investigation of the final Operable Unit for Middlesex, OU-2, Groundwater. As of December 2012, the project delivery team has completed a Supplemental Remedial Investigation, which will be followed with a streamlined Feasibility Study, Proposed Plan, and ROD. Several years of historical groundwater data was available from previous investigations and the FUSRAP Environmental Surveillance Program. Historical data indicated sporadic detections of Volatile Organic Compounds (VOCs), primarily trichloroethylene (TCE), carbon tetrachloride (CT), and methyl tert-butyl ether (MTBE), with no apparent trend or pattern indicating extent or source of the VOC impact. In 2008, the project delivery team initiated efforts to re-assess the Conceptual Site Model (CSM) for groundwater. The bedrock was re-evaluated as a leaky multi-unit aquifer, and a plan was developed for additional investigations for adequate bedrock characterization and delineation of groundwater contaminated primarily by CT, TCE, and tetrachloroethene (PCE). The investigation was designed to accumulate multiple lines of evidence to determine the source and to delineate the extent of contamination, as required to complete the CERCLA Process and gain regulatory acceptance. Investigative techniques included in-well vertical flow tracing, borehole geophysics and packer testing of temporary test holes to characterize contamination in the bedrock fractures beneath the site, and to delineate likely source areas. (authors)

Miller, David M. [ECC, 110 Fieldcrest Ave, Ste 31, Edison, NJ, 08837 (United States)] [ECC, 110 Fieldcrest Ave, Ste 31, Edison, NJ, 08837 (United States); Edge, Helen [US Army Corps of Engineers - NYD, 26 Federal Plaza, Room 1811, New York, NY, 10278 (United States)] [US Army Corps of Engineers - NYD, 26 Federal Plaza, Room 1811, New York, NY, 10278 (United States)

2013-07-01T23:59:59.000Z

227

California GAMA Program: Groundwater Ambient Monitoring and Assessment Results for the Sacramento Valley and Volcanic Provinces of Northern California  

SciTech Connect (OSTI)

In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as methyl tert butyl ether (MTBE) from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater monitoring plan, and led to the initiation of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The primary objective of the California Aquifer Susceptibility (CAS) project (under the GAMA Program) is to assess water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement this groundwater assessment program. In 2003, LLNL carried out this vulnerability study in the Sacramento Valley and Volcanic Provinces. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3 method). In addition, stable oxygen isotope measurements help determine the recharge water source location. Interpreted together, and in the context of existing water quality and hydrogeologic data, these observable parameters help define the flow field of a groundwater basin, and indicate the degree of vertical communication between near-surface sources (or potential sources) of contamination, and deeper groundwater pumped at high capacity production wells.

Moran, J E; Hudson, G B; Eaton, G F; Leif, R

2005-01-20T23:59:59.000Z

228

Assessment of ether and alcohol fuels from coal. Volume 2. Technical report  

SciTech Connect (OSTI)

A unique route for the indirect liquefaction of coal to produce transportation fuel has been evaluated. The resultant fuel includes alkyl tertiary alkyl ethers and higher alcohols, all in the gasoline boiling range. When blended into gasoline, the ether fuel provides several advantages over the lower alcohols: (1) lower chemical oxygen content, (2) less-severe water-separation problems, and (3) reduced front-end volatility effects. The ether fuel also has high-octane quality. Further, it can be utilized as a gasoline substitute in all proportions. Production of ether fuel combines several steps, all of which are or have been practiced on an industrial scale: (1) coal gasification, (2) gas cleanup and shift to desired H/sub 2/:CO ratio, (3) conversion of synthesis gas to isobutanol, methanol, and higher alcohols, (4) separation of alcohols, (5) chemical dehydration of isobutanol to isobutylene, and (6) etherification of isobutylene with methanol. A pilot-plant investigation of the isobutanol synthesis step was performed. Estimates of ether-fuel manufacturing costs indicate this process route is significantly more costly than synthesis of methanol. However, the fuel performance features provide incentive for developing the necessary process and catalyst improvements. Co-production of higher-molecular-weight co-solvent alcohols represents a less-drastic form of methanol modification to achieve improvement in the performance of methanol-gasoline blends. Costs were estimated for producing several proportions of methanol plus higher alcohols from coal. Estimated fuel selling price increases regularly but modestly with higher alcohol content.

Not Available

1983-03-01T23:59:59.000Z

229

Oxidation and methylation of dissolved elemental mercury by anaerobic bacteria  

SciTech Connect (OSTI)

Methylmercury is a neurotoxin that poses significant health risks to humans. Some anaerobic sulphate- and iron-reducing bacteria can methylate oxidized forms of mercury, generating methylmercury1-4. One strain of sulphate-reducing bacteria (Desulfovibrio desulfuricans ND132) can also methylate elemental mercury5. The prevalence of this trait among different bacterial strains and species remains unclear, however. Here, we compare the ability of two strains of the sulphate-reducing bacterium Desulfovibrio and one strain of the iron-reducing bacterium Geobacter to oxidise and methylate elemental mercury in a series of laboratory incubations. Experiments were carried out under dark, anaerobic conditions, in the presence of environmentally-relevant concentrations of elemental mercury. We report differences in the ability of these organisms to oxidise and methylate elemental mercury. In line with recent findings5, we show that Desulfovibrio desulfuricans ND132 can both oxidise and methylate elemental mercury. However, the rate of methylation of elemental mercury is only about one third the rate of methylation of oxidized mercury. We also show that Desulfovibrio alaskensis G20 can oxidise, but not methylate, elemental mercury. Geobacter sulfurreducens PCA is able to oxidise and methylate elemental mercury in the presence of cysteine. We suggest that the activity of methylating and non-methylating bacteria may together enhance the formation of methylmercury in anaerobic environments.

Hu, Haiyan [ORNL] [ORNL; Lin, Hui [ORNL] [ORNL; Zheng, Wang [ORNL] [ORNL; Tomanicek, Stephen J [ORNL] [ORNL; Johs, Alexander [ORNL] [ORNL; Feng, Xinbin [ORNL] [ORNL; Elias, Dwayne A [ORNL] [ORNL; Liang, Liyuan [ORNL] [ORNL; Liang, Liyuan [ORNL] [ORNL; Gu, Baohua [ORNL] [ORNL

2013-01-01T23:59:59.000Z

230

Process to convert biomass and refuse derived fuel to ethers and/or alcohols  

DOE Patents [OSTI]

A process is described for conversion of a feedstock selected from the group consisting of biomass and refuse derived fuel (RDF) to provide reformulated gasoline components comprising a substantial amount of materials selected from the group consisting of ethers, alcohols, or mixtures thereof, comprising: drying said feedstock; subjecting said dried feedstock to fast pyrolysis using a vortex reactor or other means; catalytically cracking vapors resulting from said pyrolysis using a zeolite catalyst; condensing any aromatic byproduct fraction; catalytically alkylating any benzene present in said vapors after condensation; catalytically oligomerizing any remaining ethylene and propylene to higher olefins; isomerizing said olefins to reactive iso-olefins; and catalytically reacting said iso-olefins with an alcohol to form ethers or with water to form alcohols. 35 figs.

Diebold, J.P.; Scahill, J.W.; Chum, H.L.; Evans, R.J.; Rejai, B.; Bain, R.L.; Overend, R.P.

1996-04-02T23:59:59.000Z

231

Process to convert biomass and refuse derived fuel to ethers and/or alcohols  

DOE Patents [OSTI]

A process for conversion of a feedstock selected from the group consisting of biomass and refuse derived fuel (RDF) to provide reformulated gasoline components comprising a substantial amount of materials selected from the group consisting of ethers, alcohols, or mixtures thereof, comprising: drying said feedstock; subjecting said dried feedstock to fast pyrolysis using a vortex reactor or other means; catalytically cracking vapors resulting from said pyrolysis using a zeolite catalyst; condensing any aromatic byproduct fraction; catalytically alkylating any benzene present in said vapors after condensation; catalytically oligomerizing any remaining ethylene and propylene to higher olefins; isomerizing said olefins to reactive iso-olefins; and catalytically reacting said iso-olefins with an alcohol to form ethers or with water to form alcohols.

Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO); Chum, Helena L. (Arvada, CO); Evans, Robert J. (Lakewood, CO); Rejai, Bahman (Lakewood, CO); Bain, Richard L. (Golden, CO); Overend, Ralph P. (Lakewood, CO)

1996-01-01T23:59:59.000Z

232

Kinetics of liquid phase catalytic dehydration of methanol to dimethyl ether  

SciTech Connect (OSTI)

This paper reports the kinetics of the liquid phase catalytic dehydration of methanol to dimethyl ether investigated. The experiments were carried out under low concentrations of feed in a 1-L stirred autoclave, according to a statistical experimental design. The inert liquid phase used for this investigation was a 78:22 blend of paraffinic and naphthenic mineral oils. A complete thermodynamic analysis was carried out in order to determine the liquid phase concentrations of the dissolved species. A global kinetic model was developed for the rate of dimethyl ether synthesis in terms of the liquid phase concentration of methanol. The activation energy of the reaction was found to be 18,830 cal/gmol. Based on a step-wise linear regression analysis of the kinetic data, the order of the reaction which gave the best fit was 0.28 with respect to methanol.

Gogate, M.R.; Lee, B.G.; Lee, S. (Akron Univ., OH (USA). Dept. of Chemical Engineering); Kulik, C.J. (Electric Power Research Inst., Palo Alto, CA (USA))

1990-01-01T23:59:59.000Z

233

2[prime] and 3[prime] Carboranyl uridines and their diethyl ether adducts  

DOE Patents [OSTI]

A process is described for preparing carboranyl uridine nucleoside compounds and their diethyl ether adducts, which exhibit a tenfold increase in boron content over prior art boron containing nucleoside compounds. The carboranyl uridine nucleoside compounds exhibit enhanced lipophilicity and hydrophilic properties adequate to enable solvation in aqueous media for subsequent incorporation of the compounds in methods for boron neutron capture therapy in mammalian tumor cells. No Drawings

Soloway, A.H.; Barth, R.F.; Anisuzzaman, A.K.; Alam, F.; Tjarks, W.

1992-12-15T23:59:59.000Z

234

Molecular modeling of the morphology and transport properties of two direct methanol fuel cell membranes: phenylated sulfonated poly(ether ether ketone ketone) versus Nafion  

SciTech Connect (OSTI)

We have used molecular dynamics simulations to examine membrane morphology and the transport of water, methanol and hydronium in phenylated sulfonated poly ether ether ketone ketone (Ph-SPEEKK) and Nafion membranes at 360 K for a range of hydration levels. At comparable hydration levels, the pore diameter is smaller, the sulfonate groups are more closely packed, the hydronium ions are more strongly bound to sulfonate groups, and the diffusion of water and hydronium is slower in Ph-SPEEKK relative to the corresponding properties in Nafion. The aromatic carbon backbone of Ph-SPEEKK is less hydrophobic than the fluorocarbon backbone of Nafion. Water network percolation occurs at a hydration level ({lambda}) of {approx}8 H{sub 2}O/SO{sub 3}{sup -}. At {lambda} = 20, water, methanol and hydronium diffusion coefficients were 1.4 x 10{sup -5}, 0.6 x 10{sup -5} and 0.2 x 10{sup -5} cm{sup 2}/s, respectively. The pore network in Ph-SPEEKK evolves dynamically and develops wide pores for {lambda} > 20, which leads to a jump in methanol crossover and ion transport. This study demonstrates the potential of aromatic membranes as low-cost challengers to Nafion for direct methanol fuel cell applications and the need to develop innovative strategies to combat methanol crossover at high hydration levels.

Devanathan, Ramaswami; Idupulapati, Nagesh B.; Dupuis, Michel

2012-08-14T23:59:59.000Z

235

Effect of solvents on the radiation-induced polymerization of ethyl and isopropyl vinyl ethers  

SciTech Connect (OSTI)

The effect of solvents on the radiation-induced cationic polymerization of ethyl and isopropyl vinyl ethers (EVE and IPVE, respectively) was investigated. EVE and IPVE polymerizations were carried out in bulk and in solution under superdry conditions in which polar impurities, especially water, have been reduced to negligible levels. This was accomplished by means of a sodium mirror technique using joint free baked out glass equipment and high vacuum. Plots of the monomer conversions and irradiation times were obtained for EVE and IPVE polymerizations in bulk and in benzene solution at constant monomer concentrations. The monomer concentration dependence of the polymerization rate was studied for EVE polymerization in bulk and in benzene, diethlyl ether, diglyme and methylene chloride, and for IPVE polymerization in bulk and in benzene. Solvent effect on the estimated propagating rate constants was examined for EVE and IPVE polymerization in bulk and in solution. The effect of temperature on the polymerization rate was also investigated for EVE polymerization in bulk ad in benzene, diethyl and diisopropyl ethers, methylene chloride and nitromethane, and for IPVE ploymerization in bulk and in benzene.

Hsieh, W.C.

1981-01-01T23:59:59.000Z

236

An Experimental and Kinetic Modeling Study of Methyl Decanoate Combustion  

SciTech Connect (OSTI)

Biodiesel is typically a mixture of long chain fatty acid methyl esters for use in compression ignition engines. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This research study presents new combustion data for methyl decanoate in an opposed-flow diffusion flame. An improved detailed chemical kinetic model for methyl decanoate combustion is developed, which serves as the basis for deriving a skeletal mechanism via the direct relation graph method. The novel skeletal mechanism consists of 648 species and 2998 reactions. This mechanism well predicts the methyl decanoate opposed-flow diffusion flame data. The results from the flame simulations indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene.

Sarathy, S M; Thomson, M J; Pitz, W J; Lu, T

2010-02-19T23:59:59.000Z

237

Analysis of dissolved benzene plumes and methyl tertiary butyl ether (MTBE) plumes in ground water at leaking underground fuel tank (LUFT) sites  

SciTech Connect (OSTI)

The 1990 Clean Air Act Amendments mandate the addition of oxygenates to gasoline products to abate air pollution. Currently, many areas of the country utilize oxygenated or reformulated fuel containing 15- percent and I I-percent MTBE by volume, respectively. This increased use of MTBE in gasoline products has resulted in accidental point source releases of MTBE containing gasoline products to ground water. Recent studies have shown MTBE to be frequently detected in samples of shallow ground water from urban areas throughout the United States (Squillace et al., 1995). Knowledge of the subsurface fate and transport of MTBE in ground water at leaking underground fuel tank (LUFT) sites and the spatial extent of MTBE plumes is needed to address these releases. The goal of this research is to utilize data from a large number of LUFT sites to gain insights into the fate, transport, and spatial extent of MTBE plumes. Specific goals include defining the spatial configuration of dissolved MTBE plumes, evaluating plume stability or degradation over time, evaluating the impact of point source releases of MTBE to ground water, and attempting to identify the controlling factors influencing the magnitude and extent of the MTBE plumes. We are examining the relationships between dissolved TPH, BTEX, and MTBE plumes at LUFT sites using parallel approaches of best professional judgment and a computer-aided plume model fitting procedure to determine plume parameters. Here we present our initial results comparing dissolved benzene and MTBE plumes lengths, the statistical significance of these results, and configuration of benzene and MTBE plumes at individual LUFT sites.

Happel, A.M.; Rice, D. [Lawrence Livermore National Lab., CA (United States); Beckenbach, E. [California Univ., Berkeley, CA (United States); Savalin, L.; Temko, H.; Rempel, R. [California State Water Resources Control Board, Sacramento, CA (United States); Dooher, B. [California Univ., Los Angeles, CA (United States)

1996-11-01T23:59:59.000Z

238

Methyl viologen radical reactions with several oxidizing agents. [Gamma Radiation  

SciTech Connect (OSTI)

The rates of oxidation of the methyl viologen radical by peroxodisulfate and hydrogen peroxide has been investigated. The methyl viologen free radical was produced by pulse radiolysis. The reaction of the peroxodisulfate radical with the methyl viologen radical was first order in both species, and the reaction rate constant is reported. A el-radiation study revealed a chain decomposition of the peroxodisulfate radical involving the methyl viologen radical when methanol, ethanol, or 2-propanol was present. Loss of the methyl viologen radical was then no longer observed to be a simple first-order reaction. The reaction of hydrogen peroxide with the methyl viologen radical was very slow in the presence of 1 M methanol. A much faster reaction in the absence of methanol was interpreted to be a reaction of the methyl viologen radical with the peroxy radicals. Hydrogen peroxide, in contrast to the chain decomposition of peroxodisulfate radicals, does not participate in a chain reaction involving the methyl viologen radical and methanol. Rate constants for the reaction of methyl viologen radical with dichromate radical, iodate radical, and ferricyanide radical are reported.

Levey, G.; Ebbesen, T.W.

1983-01-01T23:59:59.000Z

239

ORTH/VIM proteins that regulate DNA methylation are functional ubiquitin E3 ligases  

E-Print Network [OSTI]

ORTH/VIM proteins that regulate DNA methylation are functional ubiquitin E3 ligases Edward Kraft1 methylation status in vivo. Keywords: RING, E3 ligase, DNA methylation, ubiquitylation, ORTH/VIM, SRA

Jacobsen, Steve

240

High temperature concrete composites containing organosiloxane crosslinked copolymers  

DOE Patents [OSTI]

This invention relates to high temperature polymer concrete composites comprising about 10-30% by weight of a liquid monomer mixture consisting essentially of an organosiloxane polymer crosslinked with an olefinically unsaturated monomer selected from the group consisting of styrene, methyl methacrylate, trimethylolpropane trimethacrylate, triallyl cyanurate, n-phenylmalimide, divinyl benzene and mixtures theroef; and about 70-90% by weight of an inert inorganic filler system containing silica sand and preferably a member selected from the group consisting of portland cement, Fe.sub.2 O.sub.3, carbon black and mixtures thereof; and optionally a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide and other organic peroxides to initiate crosspolymerization of the monomer mixture in the presence of the inorganic filler.

Zeldin, Arkady (Rego Park, NY); Carciello, Neal (Patchogue, NY); Kukacka, Lawrence (Port Jefferson, NY); Fontana, Jack (Shoreham, NY)

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Host cells and methods for producing 3-methyl-2-buten-1-ol, 3-methyl-3-buten-1-ol, and 3-methyl-butan-1-ol  

DOE Patents [OSTI]

The invention provides for a method for producing a 5-carbon alcohol in a genetically modified host cell. In one embodiment, the method comprises culturing a genetically modified host cell which expresses a first enzyme capable of catalyzing the dephosphorylation of an isopentenyl pyrophosphate (IPP) or dimethylallyl diphosphate (DMAPP), such as a Bacillus subtilis phosphatase (YhfR), under a suitable condition so that 5-carbon alcohol is 3-methyl-2-buten-1-ol and/or 3-methyl-3-buten-1-ol is produced. Optionally, the host cell may further comprise a second enzyme capable of reducing a 3-methyl-2-buten-1-ol to 3-methyl-butan-1-ol, such as a reductase.

Chou, Howard H. (Berkeley, CA); Keasling, Jay D. (Berkeley, CA)

2011-07-26T23:59:59.000Z

242

E-Print Network 3.0 - arsenic methylation profiles Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: , urinary arsenic methylation profiles, and urothelial carcinoma susceptibility. Food Chem. Toxicol. 46, 929... and in vitro studies suggest that methylated arsenic...

243

High octane ethers from synthesis gas-derived alcohols. Quarterly technical progress report, April--June 1993  

SciTech Connect (OSTI)

The results shown in Figures 10 and 11 demonstrate that the formation of butenes was very sensitive to the alcohol partial pressure. A small elevation of the alcohol pressure suppressed the formation of butenes rather drastically at both 90 and 117{degree}C. The synthesis rates of DME, MIBE, and MTBE ethers were not significantly affected at 90{degree}C, although there was a trend to increase the space time yield of DME as the alcohol pressure was increased. At the reaction temperature of 117{degree}C, all of the ethers showed increasing productivities as the pressure of the reactants was increased (Figure 11). An isotope labelling experiment was carried out to provide mechanistic insight into the manner in which methanol and isobutanol react together to form DME, MIBE, and MTBE ethers and to determine if MTBE were derived from MIBE.

Klier, K.; Herman, R.G.; Menszak, J.; Johansson, M.A.; Feeley, O.C.; Kim, D.

1993-07-01T23:59:59.000Z

244

Commercial-scale demonstration of the Liquid Phase Methanol (LPMEOH{trademark}) Process. Peroxide formation of dimethyl ether in methanol mixtures  

SciTech Connect (OSTI)

Organic peroxides could form when dimethyl ether in methanol is stored for three to six months at a time. The objective of this work was to determine the level of peroxide formation from dimethyl ether in reagent grade methanol and raw methanol at room temperature under 3 atmospheres (45 psig) of air. Raw methanol is methanol made from syngas by the LPMEOH Process without distillation. Aliphatic ethers tend to react slowly with oxygen from the air to form unstable peroxides. However, there are no reports on peroxide formation from dimethyl ether. After 172 days of testing, dimethyl ether in either reagent methanol or raw methanol at room temperature and under 60--70 psig pressure of air does not form detectable peroxides. Lack of detectable peroxides suggests that dimethyl ether or dimethyl ether and methanol may be stored at ambient conditions. Since the compositions of {approximately} 1.3 mol% or {approximately} 4.5 mol% dimethyl ether in methanol do not form peroxides, these compositions can be considered for diesel fuel or an atmospheric turbine fuel, respectively.

Waller, F.J.

1997-11-01T23:59:59.000Z

245

Calixarene crown ether solvent composition and use thereof for extraction of cesium from alkaline waste solutions  

DOE Patents [OSTI]

A solvent composition and corresponding method for extracting cesium (Cs) from aqueous neutral and alkaline solutions containing Cs and perhaps other competing metal ions is described. The method entails contacting an aqueous Cs-containing solution with a solvent consisting of a specific class of lipophilic calix[4]arene-crown ether extractants dissolved in a hydrocarbon-based diluent containing a specific class of alkyl-aromatic ether alcohols as modifiers. The cesium values are subsequently recovered from the extractant, and the solvent subsequently recycled, by contacting the Cs-containing organic solution with an aqueous stripping solution. This combined extraction and stripping method is especially useful as a process for removal of the radionuclide cesium-137 from highly alkaline waste solutions which are also very concentrated in sodium and potassium. No pre-treatment of the waste solution is necessary, and the cesium can be recovered using a safe and inexpensive stripping process using water, dilute (millimolar) acid solutions, or dilute (millimolar) salt solutions. An important application for this invention would be treatment of alkaline nuclear tank wastes. Alternatively, the invention could be applied to decontamination of acidic reprocessing wastes containing cesium-137.

Moyer, Bruce A. (Oak Ridge, TN); Sachleben, Richard A. (Knoxville, TN); Bonnesen, Peter V. (Knoxville, TN); Presley, Derek J. (Ooltewah, TN)

2001-01-01T23:59:59.000Z

246

Methyl bromide emissions to the atmosphere from temperate woodland ecosystems   

E-Print Network [OSTI]

The environmental importance of methyl bromide (CH3Br) arises from its contribution to stratospheric ozone loss processes and, as a consequence, its emissions from anthropogenic sources are subject to the Montreal Protocol. A better understanding...

Drewer, Julia; Heal, Kate V; Smith, Keith A; Heal, Mathew R

2008-01-01T23:59:59.000Z

247

The Genetics of de novo Methylation in Arabidopsis thaliana  

E-Print Network [OSTI]

domains akin to UHRF1 and the VIM proteins. These proteinsthe VARIANT IN METHYLATION (VIM) family. In higher orderUHRF1 in mammal or the VIM proteins in plants. UHRF1/VIM

Greenberg, Maxim Van Cleef

2012-01-01T23:59:59.000Z

248

Regulation of yeast development by mRNA methylation  

E-Print Network [OSTI]

The internal methylation of mRNA post-transcriptionally is an essential component of the mRNA editing machinery in virtually every eukaryotic system. Despite this ubiquity, little is known about the relevance, consequences ...

Agarwala, Sudeep D

2012-01-01T23:59:59.000Z

249

akap12 promoter methylation: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(MEK) with hydrogen peroxide (H2O2), is widely used in industry as a radicalThermal Hazard Analysis of Methyl Ethyl Ketone Peroxide Ron-Hsin Chang, Chi-Min Shu and Po-Yin Yeh...

250

Control of mercury methylation in wetlands through iron addition  

E-Print Network [OSTI]

Mason, R. P. ; Flegal, A. R. , Mercury speciation in the SanP. ; Flegal, A. R. , Decadal mercury trends in San FranciscoP. G. ; Nelson, D. C. , Mercury methylation from unexpected

Sedlak, David L; Ulrich, Patrick D

2009-01-01T23:59:59.000Z

251

Methyl arsenic adsorption and desorption behavior on iron oxides  

E-Print Network [OSTI]

METHYL ARSENIC ADSORPTION AND DESORPTION BEHAVIOR ON IRON OXIDES A Thesis by BRANDON JAMES LAFFERTY Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 2004 Major Subject: Soil Science METHYL ARSENIC ADSORPTION AND DESORPTION BEHAVIOR ON IRON OXIDES A Thesis by BRANDON JAMES LAFFERTY Submitted to Texas A&M University...

Lafferty, Brandon James

2005-08-29T23:59:59.000Z

252

The synthesis of some N-methylated aminoalkylphosphonic acids  

E-Print Network [OSTI]

(XLIII) were o heated with diethyl hydrogenphosphonate (XVI) at approximately 100 until the evolution of dimethylarnine (XXX) ceased. The 1-dimethyl- amino 1-alkenes (XLIV) reacted exothermically with diethyl hydro- genphosphonate (XVI) once... exothermically with methyl iodide at room temperature whereas the other eaters, which contained more bulky (R) substituents, did not. Secondly, the betaine obtained m the highest yield, N, N, N-trimethyl-N-(phosphono- methyl)ammonium hydroxide, mner salt...

Eikenberry, Jon Nathan

1966-01-01T23:59:59.000Z

253

Title: Decomposition of ethanol and dimethyl-ether during CVD synthesis of single-walled carbon nanotubes  

E-Print Network [OSTI]

of ethanol and dimethyl-ether during CVD synthesis of single-walled carbon nanotubes Author list: Bo Hou (single-walled carbon nanotubes) was investigated. Gas-phase thermal decomposition of ethanol and DME ethanol and DME decomposition, confirming expected reaction trends and primary byproducts. Peak

Maruyama, Shigeo

254

Process for the production of ethylidene diacetate from dimethyl ether using a heterogeneous catalyst  

DOE Patents [OSTI]

This invention relates to a process for producing ethylidene diacetate by the reaction of dimethyl ether, acetic acid, hydrogen and carbon monoxide at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that is stable to hydrogenation and comprises an insoluble polymer having pendant quaternized heteroatoms, some of which heteroatoms are ionically bonded to anionic Group VIII metal complexes, the remainder of the heteroatoms being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for 3 consecutive runs without loss in activity.

Ramprasad, D.; Waller, F.J.

1998-04-28T23:59:59.000Z

255

Use of aluminum phosphate as the dehydration catalyst in single step dimethyl ether process  

DOE Patents [OSTI]

The present invention pertains to a process for the coproduction of methanol and dimethyl ether (DME) directly from a synthesis gas in a single step (hereafter, the "single step DME process"). In this process, the synthesis gas comprising hydrogen and carbon oxides is contacted with a dual catalyst system comprising a physical mixture of a methanol synthesis catalyst and a methanol dehydration catalyst. The present invention is an improvement to this process for providing an active and stable catalyst system. The improvement comprises the use of an aluminum phosphate based catalyst as the methanol dehydration catalyst. Due to its moderate acidity, such a catalyst avoids the coke formation and catalyst interaction problems associated with the conventional dual catalyst systems taught for the single step DME process.

Peng, Xiang-Dong (Allentown, PA); Parris, Gene E. (Coopersburg, PA); Toseland, Bernard A. (Allentown, PA); Battavio, Paula J. (Allentown, PA)

1998-01-01T23:59:59.000Z

256

Process for the production of ethylidene diacetate from dimethyl ether using a heterogeneous catalyst  

DOE Patents [OSTI]

This invention relates to a process for producing ethylidene diacetate by the reaction of dimethyl ether, acetic acid, hydrogen and carbon monoxide at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that is stable to hydrogenation and comprises an insoluble polymer having pendant quaternized heteroatoms, some of which heteroatoms are ionically bonded to anionic Group VIII metal complexes, the remainder of the heteroatoms being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for 3 consecutive runs without loss in activity.

Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

1998-01-01T23:59:59.000Z

257

Nested methylation-specific polymerase chain reaction cancer detection method  

DOE Patents [OSTI]

A molecular marker-based method for monitoring and detecting cancer in humans. Aberrant methylation of gene promoters is a marker for cancer risk in humans. A two-stage, or "nested" polymerase chain reaction method is disclosed for detecting methylated DNA sequences at sufficiently high levels of sensitivity to permit cancer screening in biological fluid samples, such as sputum, obtained non-invasively. The method is for detecting the aberrant methylation of the p16 gene, O 6-methylguanine-DNA methyltransferase gene, Death-associated protein kinase gene, RAS-associated family 1 gene, or other gene promoters. The method offers a potentially powerful approach to population-based screening for the detection of lung and other cancers.

Belinsky, Steven A. (Albuquerque, NM); Palmisano, William A. (Edgewood, NM)

2007-05-08T23:59:59.000Z

258

Methods for detection of methyl-CpG dinucleotides  

DOE Patents [OSTI]

The invention provides methods for enriching methyl-CpG sequences from a DNA sample. The method makes use of conversion of cytosine residues to uracil under conditions in which methyl-cytosine residues are preserved. Additional methods of the invention enable to preservation of the context of me-CpG dinucleotides. The invention also provides a recombinant, full length and substantially pure McrA protein (rMcrA) for binding and isolation of DNA fragments containing the sequence 5'-C.sup.MeCpGG-3'. Methods for making and using the rMcrA protein, and derivatives thereof are provided.

Dunn, John J.

2013-01-29T23:59:59.000Z

259

Methods for detection of methyl-CpG dinucleotides  

DOE Patents [OSTI]

The invention provides methods for enriching methyl-CpG sequences from a DNA sample. The method makes use of conversion of cytosine residues to uracil under conditions in which methyl-cytosine residues are preserved. Additional methods of the invention enable to preservation of the context of me-CpG dinucleotides. The invention also provides a recombinant, full length and substantially pure McrA protein (rMcrA) for binding and isolation of DNA fragments containing the sequence 5'-C.sup.MeCpGG-3'. Methods for making and using the rMcrA protein, and derivatives thereof are provided.

Dunn, John J

2013-11-26T23:59:59.000Z

260

Methods for detection of methyl-CpG dinucleotides  

DOE Patents [OSTI]

The invention provides methods for enriching methyl-CpG sequences from a DNA sample. The method makes use of conversion of cytosine residues to uracil under conditions in which methyl-cytosine residues are preserved. Additional methods of the invention enable to preservation of the context of me-CpG dinucleotides. The invention also provides a recombinant, full length and substantially pure McrA protein (rMcrA) for binding and isolation of DNA fragments containing the sequence 5'-C.sup.MeCpGG-3'. Methods for making and using the rMcrA protein, and derivatives thereof are provided.

Dunn, John J.

2012-09-11T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Effects of hydration water on protein methyl group dynamics insolution  

SciTech Connect (OSTI)

Elastic and quasielastic neutron scattering experiments have been used to investigate the dynamics of methyl groups in a protein-model hydrophobic peptide in solution. The results suggest that, when the hydrophobic side chains are hydrated by a single hydration water layer, the only allowed motions are confined and attributed to librational and rotational movement associated with the methyl groups. They provide unique experimental evidence that the structural and dynamical properties of the interfacial water strongly influence the side-chain dynamics and the activation of diffusive motion.

Russo D; Hura GL; Copley JRD

2007-01-01T23:59:59.000Z

262

Coordination effect-regulated CO2 capture with an alkali metal onium salts/crown ether system  

SciTech Connect (OSTI)

A coordination effect was employed to realize equimolar CO2 absorption, adopting easily synthesized amino group containing absorbents (alkali metal onium salts). The essence of our strategy was to increase the steric hindrance of cations so as to enhance a carbamic acid pathway for CO2 capture. Our easily synthesized alkali metal amino acid salts or phenolates were coordinated with crown ethers, in which highly sterically hindered cations were obtained through a strong coordination effect of crown ethers with alkali metal cations. For example, a CO2 capacity of 0.99 was attained by potassium prolinate/18-crown-6, being characterized by NMR, FT-IR, and quantum chemistry calculations to go through a carbamic acid formation pathway. The captured CO2 can be stripped under very mild conditions (50 degrees C, N-2). Thus, this protocol offers an alternative for the development of technological innovation towards efficient and low energy processes for carbon capture and sequestration.

Yang, Zhen-Zhen [Nankai University China] [Nankai University China; Jiang, Deen [ORNL] [ORNL; Zhu, Xiang [ORNL] [ORNL; Tian, Chengcheng [ORNL] [ORNL; Brown, Suree [ORNL] [ORNL; Do-Thanh, Chi-Linh [The University of Tennessee] [The University of Tennessee; He, Liang-Nian [Nankai University China] [Nankai University China; Dai, Sheng [ORNL] [ORNL

2014-01-01T23:59:59.000Z

263

Carbon-carbon bond cleavage of 1,2-hydroxy ethers b7 vanadium(V) dipicolinate complexes  

SciTech Connect (OSTI)

The development of alternatives to current petroleum-based fuels and chemicals is becoming increasingly important due to concerns over climate change, growing world energy demand, and energy security issues. Using non-food derived biomass to produce renewable feedstocks for chemicals and fuels is a particularly attractive possibility. However, the majority of biomass is in the form of lignocellulose, which is often not fully utilized due to difficulties associated with breaking down both lignin and cellulose. Recently, a number of methods have been reported to transform cellulose directly into more valuable materials such as glucose, sorbitol, 5-(chloromethyl)furfural, and ethylene glycol. Less progress has been made with selective transformations of lignin, which is typically treated in paper and forest industries by kraft pulping (sodium hydroxide/sodium sulfide) or incineration. Our group has begun investigating aerobic oxidative C-C bond cleavage catalyzed by dipicolinate vanadium complexes, with the idea that a selective C-C cleavage reaction of this type could be used to produce valuable chemicals or intermediates from cellulose or lignin. Lignin is a randomized polymer containing methoxylated phenoxy propanol units. A number of different linkages occur naturally; one of the most prevalent is the {beta}-O-4 linkage shown in Figure 1, containing a C-C bond with 1,2-hydroxy ether substituents. While the oxidative C-C bond cleavage of 1,2-diols has been reported for a number of metals, including vanadium, iron, manganese, ruthenium, and polyoxometalate complexes, C-C bond cleavage of 1,2-hydroxy ethers is much less common. We report herein vanadium-mediated cleavage of C-C bonds between alcohol and ether functionalities in several lignin model complexes. In order to explore the scope and potential of vanadium complexes to effect oxidative C-C bond cleavage in 1,2-hydroxy ethers, we examined the reactivity of the lignin model complexes pinacol monomethyl ether (A), 2-phenoxyethanol (B), and 1,2-diphenyl-2-methoxyethanol (C) (Figure 1). Reaction of (dipic)V{sup V}(O)O{sup i}Pr (1a) or (dipic)V{sup v}(O)OEt (lb) with A, B, or C in acetonitrile yielded new vanadium(V) complexes where the alcohol-ether ligand was bound in a chelating fashion. From the reaction of 1b with pinacol monomethyl ether (A) in acetonitrile solution, (dipic)V{sup v}(O)(pinOMe) (2) (PinOMe = 2,3-dimethyl-3-methoxy-2-butanoxide) was isolated in 61 % yield. Reaction of 1b with 2-phenoxyethanol (B) in acetonitrile gave the new complex (dipic)V{sup v}(O)(OPE) (3) (OPE = 2-phenoxyethoxide), which was isolated in 76% yield. In a similar fashion, 1a reacted with 1,2-diphenyl-2-methoxyethanol (C) to give (dipic)V(O)(DPME) (4) (DPME = 1,2-diphenyl-2-methoxyethoxide), which was isolated in 39% yield. Complexes 2, 3, and 4 were characterized by {sup 1}H NMR and IR spectroscopy, elemental analysis, and X-ray crystallography. Compared to the previously reported vanadium(V) pinacolate complex (dipic)V(O)(pinOH) the X-ray structure of complex 2 reveals a slightly shorter V = O bond, 1.573(2) {angstrom} vs 1.588(2) {angstrom} for the pinOH structure. Complexes 3 and 4 display similar vanadium oxo bond distances of 1.568(2) {angstrom} and 1.576(2) {angstrom}, respectively. All three complexes show longer bonds to the ether-oxygen trans to the oxo (2.388(2) {angstrom} for 2, 2.547(2) {angstrom} for 3, and 2.438(2) {angstrom} for 4) than to the hydroxy-oxygen in the pinOH structure (2.252(2) {angstrom}).

Hanson, Susan K [Los Alamos National Laboratory; Gordon, John C [Los Alamos National Laboratory; Thorn, David L [Los Alamos National Laboratory; Scott, Brian L [Los Alamos National Laboratory; Baker, R Tom [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

264

E-Print Network 3.0 - asymmetric dimethyl arginine-dimethylarginine...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

methyl acetate is selectively produced by reaction of dimethyl ether with carbon monoxide... .; "Superacid-Catalyzed Carbonylation of Methane, Methyl Halides, Methyl Alcohol,...

265

Freezing of Dynamics of a Methyl Group in a Protein Hydrophobic...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Freezing of Dynamics of a Methyl Group in a Protein Hydrophobic Core at Cryogenic Temperatures by Deuteron NMR Spectroscopy. Freezing of Dynamics of a Methyl Group in a Protein...

266

Environmental and age effects on methylation changes in human brain and blood cells  

E-Print Network [OSTI]

Previous studies have shown that DNA methylation may 1 e associated with disease, aging, the rate of aging and genetics. In this thesis, age is accurately predicted from DNA methylation in brain and blood tissues using two ...

Giguzinsky, Orit

2014-01-01T23:59:59.000Z

267

Ultrafast photochemistry of methyl hydroperoxide on ice particles  

E-Print Network [OSTI]

Ultrafast photochemistry of methyl hydroperoxide on ice particles M. A. Kambouresa , S. AOOH, on water clusters produces a surprisingly wide range of products on a subpicosecond time scale | photodissociation Photoinduced processes at surfaces of water or ice are of interest in atmospheric chemistry

Nizkorodov, Sergey

268

Thermophysical properties of 2,2,2-trifluoroethanol + tetraethylene glycol dimethyl ether  

SciTech Connect (OSTI)

Isothermal P,x data from 303.15 K to 423.15 K, liquid densities from 283.15 K to 423.15 K, and dynamic viscosities from 343.15 K to 393.15 K for the binary system 2,2,2-trifluoroethanol + tetraethylene glycol dimethyl ether were measured. The vapor-liquid equilibrium (VLE) data were measured. The vapor-liquid equilibrium (VLE) data were measured using a static apparatus. VLE data were correlated by the five-parameter NRTL equation, while density and kinematic viscosity data were correlated with temperature and liquid composition using empirical equations. The viscosity data used in the correlation cover the range of 293.15--393.15 K. VLE data indicate that this binary system exhibits large negative deviations from Raoult`s law. These mixtures present large exothermic excess molar enthalpies. The excess molar enthalpy calculated using the Gibbs-Helmholtz equation and the NRTL parameters was compared with experimental data existing in the literature.

Herraiz, J.; Olive, F.; Zhu, S.; Shen, S.; Coronas, A. [Univ. Rovira i Virgili, Tarragona (Spain). Dept. of Mechanical Engineering] [Univ. Rovira i Virgili, Tarragona (Spain). Dept. of Mechanical Engineering

1999-07-01T23:59:59.000Z

269

Phase 1 Methyl Iodide Deep-Bed Adsorption Tests  

SciTech Connect (OSTI)

Nuclear fission results in the production of fission products (FPs) and activation products including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Research, demonstrations, and some reprocessing plant experience have indicated that diatomic iodine can be captured with efficiencies high enough to meet regulatory requirements. Research on the capture of organic iodides has also been performed, but to a lesser extent [Jubin 2012b]. Several questions remain open regarding the capture of iodine bound in organic compounds. Deep-bed methyl iodide adsorption testing has progressed according to a multi-laboratory methyl iodide adsorption test plan. This report summarizes the first phase of methyl iodide adsorption work performed according to this test plan using the deep-bed iodine adsorption test system at the Idaho National Laboratory (INL), performed during Fiscal Year (FY) 2013 and early FY-2014. Testing has been performed to address questions posed in the test plan, and followed the testing outline in the test plan. Tests established detection limits, developed procedures for sample analysis with minimal analytical interferences, and confirmed earlier results that show that the methyl iodide reacts when in contact with the AgZ sorbent, and not significantly in the gas flow upstream of the sorbent. The reaction(s) enable separation of the iodine from the organic moiety, so that the iodine can chemisorb onto the sorbent. The organic moiety can form other compounds, some of which are organic compounds that are detected and can be tentatively identified using GC-FID and GCMS. Test results also show that other gas constituents (NOx and/or H2O) can affect the methyl iodide reactions. With NOx and H2O present in the gas stream, the majority of uncaptured iodine exiting iodine-laden sorbent beds is in the form of I2 or HI, species that are soluble in NaOH scrubbing solution for iodine analysis. But when NOx and H2O are not present, then the majority of the uncaptured iodine exiting iodine-laden sorbent is in the form of methyl iodide. Methyl iodide adsorption efficiencies have been high enough so that initial DFs exceed 1,000 to 10,000. The methyl iodide mass transfer zone depths are estimated at 4-8 inches, possibly deeper than mass transfer zone depths estimated for I2 adsorption on AgZ. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption under various conditions specified in the methyl iodide test plan, and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

Nick Soelberg; Tony Watson

2014-08-01T23:59:59.000Z

270

Mechanistic Investigation of Acid-Catalyzed Cleavage of Aryl-Ether Linkages: Implications for Lignin Depolymerization  

SciTech Connect (OSTI)

Carbon-oxygen bonds are the primary inter-monomer linkages lignin polymers in plant cell walls, and as such, catalyst development to cleave these linkages is of paramount importance to deconstruct biomass to its constituent monomers for the production of renewable fuels and chemicals. For many decades, acid catalysis has been used to depolymerize lignin. Lignin is a primary component of plant cell walls, which is connected primarily by aryl-ether linkages, and the mechanism of its deconstruction by acid is not well understood, likely due to its heterogeneous and complex nature compared to cellulose. For effective biomass conversion strategies, utilization of lignin is of significant relevance and as such understanding the mechanisms of catalytic lignin deconstruction to constituent monomers and oligomers is of keen interest. Here, we present a comprehensive experimental and theoretical study of the acid catalysis of a range of dimeric species exhibiting the b-O-4 linkage, the most common inter-monomer linkage in lignin. We demonstrate that the presence of a phenolic species dramatically increases the rate of cleavage in acid at 150 degrees C. Quantum mechanical calculations on dimers with the para-hydroxyl group demonstrate that this acid-catalyzed pathway differs from the nonphenolic dimmers. Importantly, this result implies that depolymerization of native lignin in the plant cell wall will proceed via an unzipping mechanism wherein b-O-4 linkages will be cleaved from the ends of the branched, polymer chains inwards toward the center of the polymer. To test this hypothesis further, we synthesized a homopolymer of b-O-4 with a phenolic hydroxyl group, and demonstrate that it is cleaved in acid from the end containing the phenolic hydroxyl group. This result suggests that genetic modifications to lignin biosynthesis pathways in plants that will enable lower severity processes to fractionate lignin for upgrading and for easier access to the carbohydrate fraction of the plant cell wall.

Sturgeon, M. R.; Kim, S.; Chmely, S. C.; Foust, T. D.; Beckham, G. T.

2013-01-01T23:59:59.000Z

271

The lightness of being: mass, ether, and unification of the forces  

SciTech Connect (OSTI)

How can an electron be both a wave and a particle? At the same time? Because it is a quantum field. That key insight seems to be underappreciated, given the awe and mysticism that permeate most nontechnical discussions of modern physics. Perhaps the root of the problem is that most popularizations of quantum mechanics and of particle physics shy away from quantized fields, the natural language for microscopic phenomena. In 'The Lightness of Being: Mass, Ether, and the Unification of Forces', Frank Wilczek confronts quantum field theory head on, demystifying not only wave-particle duality but also the origin of mass for hadrons (that is, everyday matter). Wilczek is the Herman Feshbach Professor of Physics at MIT and a co-recipient of the 2004 Nobel Prize in Physics. His research has spanned almost all aspects of theoretical particle physics, with significant forays into condensed-matter physics and dense nuclear matter (condensed quark matter, one might say). Recurring themes are the richness of quantum chromodynamics (QCD) and the alluring ideas of unification. His breadth and depth make him a sought after speaker for colloquia and public lectures. Wilczek also contributes an occasional Reference Frame column to 'Physics Today'. The material in 'The Lightness of Being' reflects the scope of the author's research. The book consists of three parts: the quantum fields of QCD (the ether that makes mass), gravitation (the ether that feels mass), and unification. Part 1, which traces notions of mass from Isaac Newton's time through theoretical and computational results of the past 40 years, is the most substantial and original; it is rich, modern, and rooted in observed phenomena. Part 2 continues in the same vein as it connects gravity, also an observed phenomenon, to QCD. Part 3 is more conventional, for a popularization of particle physics, in its focus on speculative ideas that (still) await direct experimental tests. Readers of 'Physics Today' will know that Wilczek can write with wit, grace, and an uncanny facility for using lightweight language to express heavy-duty ideas. They will find much of that kind of writing in 'The Lightness of Being'. Wilczek addresses subtle ideas with vim and vigor. He avoids some of the jargon of quantum field theory; for example, he calls the vertex in a Feynman diagram a hub. In more ambitious terminology, he refers to space-filling, everfluctuating quantum fields--be they electrons, quarks, gluons, or gravity--as 'the Grid'. The term is supposed to be short and familiar, evoking the ubiquitous electric grid (and soon-to-beubiquitous computing grid). It also, for the expert, cleverly alludes to lattice gauge theory. Indeed, after vividly explaining how the dynamics of QCD and the constraints of Heisenberg uncertainty conspire to create mass from the Grid, Wilczek emphasizes that the picture is backed by lattice QCD computations of 'heroic' proportions. Unfortunately, too much of 'The Lightness' is laden with clunky affectation: silly names (a pulsed electron accelerator is called the 'ultrastroboscopic nanomicroscope'), sophomoric jokes ('hadron' is 'not a typo'), references to pop culture (Wilczek might have called quantum fields 'the Matrix, but the sequels tarnished that candidate'), and many pointless footnotes. In a public lecture the audience may guffaw at such jokes, but on the printed page they fall flat. Wilczek explains physics so well that the inappropriate humor is the biggest unexplained puzzle of the book. It is fine to be silly, even crude, as long as the reader's path to understanding is made easier. A joke can inform with an unexpected perspective or simply give the mind a pause to refresh. Some of the humor achieves such aims, but too many gags impede the pace of the otherwise fine exposition. Three appendices, a glossary, and a set of endnotes are crisp and sober. They are excellent. 'The Lightness of Being' is not unbearable, but it is weighed down with too much clutter to rank as a masterpiece. It's a pity: Wilczek's best writing--some of it in this book--is l

Kronfeld, Andreas S.

2009-03-01T23:59:59.000Z

272

SYNTHESIS OF NOVEL CROWN ETHERS BEARING THE exo-cis-2,3-NORBORNYL GROUP AS POTENTIAL Na+ AND K+ EXTRACTANTS  

SciTech Connect (OSTI)

The synthesis of a series of novel dinorbornyl-16-crown-5 and dinorbornyl-18-crown-6 ethers that incorporate the exo-cis-2,3-norbornyl moiety within the macrocycle framework is described. The key starting material for the crown ethers, exo-cis-2,3-norbornanediol, was successfully prepared on a large (>30g) scale in 88% yield from norbornylene by osmium tetroxide-catalyzed hydroxylation. The syn and anti isomers of the dinorbornyl-16-crown-5 ether family were prepared using diethylene glycol with ring closure achieved using a methallyl linkage. The isomers cis-syn-cis and cis-anti-cis di-norbornano-15-methyleno-16-crown-5 (6A and 6B) could be separated using column chromatography, and a single crystal of the syn isomer 6A suitable for X-ray crystal structure analysis was obtained, thereby confi rming the syn orientation. The syn and anti isomers of the dinorbornyl-18-crown-6 ether family were successfully prepared employing a different synthetic strategy, involving the potassium–templated cyclization of two bis-hydroxyethoxy-substituted exo-cis-2,3-norbornyl groups under high dilution conditions. Attempts to fully separate cis-syn-cis di-norbornano-18-crown-6 (10A) and cis-anti-cis di-norbornano-18-crown-6 (10B) from one another using column chromatography were unsuccessful. All intermediates and products were checked for purity using either thin layer chromatography or gas chromatography, and characterized by proton and carbon NMR. Crown ethers 6AB and 10AB are to our knowledge the fi rst crown ethers to incorporate the exo-cis-2,3-norbornyl moiety into the crown ring to be successfully synthesized and characterized.

Robeson, R.M.; Bonnesen, P.

2007-01-01T23:59:59.000Z

273

Mercury Methylation in Mine Wastes Collected from Abandoned Mercury Mines in the USA  

SciTech Connect (OSTI)

Mercury mines contain highly elevated Hg contents, but more problematic environmentally are elemental Hg and soluble Hg salts produced during ore retorting that remain in wastes at mine sites. Under certain conditions, these inorganic Hg compounds convert to bioavailable, highly toxic organic Hg forms. Speciation and transformation of Hg was studied in wastes collected from abandoned Hg mines at McDermitt, NV, and Terlingua, TX, which are moderate size on an international scale and produced about 10,000 and 5,000 t of elemental Hg, respectively. In waste samples, we measured total Hg and methyl-Hg contents, identified various Hg compounds using Hg-thermo-desorption pyrolysis, and determined rates of Hg methylation and methyl-Hg demethylation using isotopic-tracer methods. Pyrolysis analysis of mine wastes showed variable amounts of cinnabar, metacinnabar, Hg salts, elemental Hg, and elemental Hg sorbed onto particulates such as clay and Fe-oxides. Mine wastes with the highest methyl-Hg contents correspond to those with elemental Hg and particulate-sorbed elemental Hg, and also produced the highest laboratory-estimated potential Hg methylation rates, as much as 4.8%/day. Samples containing dominantly cinnabar showed little or no Hg methylation. Mine wastes with high methyl-Hg contents generally showed low methyl-Hg demethylation, suggesting that Hg methylation was dominant. Both mines are located in semiarid climates, and during this study, streambeds below the mines were dry. Total Hg contents in stream sediment collected below the mines show significant dilution, and methyl-Hg contents were typically below the limit of determination. Methylation of Hg downstream from Hg mines is probably lower in arid climates due to lack of mine-water runoff and lower microbial activity. The correspondence of mine wastes containing elemental Hg and high methyl-Hg contents suggests that Hg0 oxidizes to Hg2+, which is subsequently bioavailable for microbial Hg methylation.

Gray, John E. (U.S. Geological Survey); Hines, Mark E. (Massachusetts, Univ Of); Biester, Harald (Heidelberg College); Lasorsa, Brenda K. (BATTELLE (PACIFIC NW LAB))

2003-05-01T23:59:59.000Z

274

Metal catalyzed copolymerization processes involving carbon oxides as substrates  

E-Print Network [OSTI]

backbone and electron donating tert-butyl groups in the phenolate rings. This catalyst was used to investigate the effect of altering the nature of the cocatalyst and its concentration. The coupling of carbon monoxide and aziridines has been shown...

Phelps, Andrea Lee

2005-11-01T23:59:59.000Z

275

Accelerated Luminophore Discovery through Combinatorial Michael S. Lowry, William R. Hudson, Robert A. Pascal, Jr., and Stefan Bernhard*  

E-Print Network [OSTI]

. There are three electrochemical stages associated with light emission in a diode-type device: (1) charge injection,4-di-tert-butyl-2,2-dipyridyl), marking the highest emission energy from a single-layer device, to date

Bernhard, Stefan

276

High-resolution infrared measurements on HSOH: Analysis of the OH fundamental vibrational mode  

E-Print Network [OSTI]

-wave spectroscopy on HSOH and H34 SOH [1]. The authors used flash vacuum pyrolysis of di-tert-butyl sulfoxide] identified five of six fundamental vibrational modes of matrix isolated HSOH formed by pyrolysis of di

Giesen, Thomas

277

Soluble hyperbranched grafts on polyethylene surfaces  

E-Print Network [OSTI]

Here we report two methods to synthesize hyperbranched poly(acrylic acid) grafts on polyethylene films and powders. The previously reported route using ?,[]-diaminopoly(tert-butyl acrylate) was repeated and all previous results were confirmed...

Britton, Danielle M

2002-01-01T23:59:59.000Z

278

E-Print Network 3.0 - acibenzolar-s-methyl para controle Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

a coffee-leaf extract formulation in tomato Summary: ), acibenzolar-S-methyl (Bion) or water (control) and three days subsequently infected with the tomato pathogen... in the...

279

Durability of Poly (Methyl Methacrylate) Lenses Used in Concentrating Photovoltaics (Presentation)  

SciTech Connect (OSTI)

This presentation reports the findings of NREL's screen test to characterize the durability of poly (methyl methacrylate) lenses used in concentrated photovoltaics.

Miller, D.; Gedvilas, L.; To, B.; Kennedy, C.; Kurtz, S.

2010-10-21T23:59:59.000Z

280

E-Print Network 3.0 - anhydroecgonine methyl ester Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Idaho Collection: Environmental Sciences and Ecology 9 A Novel Post-translational Modification of Yeast Elongation Factor 1A Summary: that is released as volatile methyl groups...

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

(2/94)(2-4,9/95)(7/97)(11,12/98)(1,9,11/99) Neuman Chapter 3 Haloalkanes, Alcohols, Ethers, and Amines  

E-Print Network [OSTI]

, Ethers, and Amines from Organic Chemistry by Robert C. Neuman, Jr. Professor of Chemistry, emeritus://web.chem.ucsb.edu/~neuman/orgchembyneuman/> Chapter Outline of the Book ************************************************************************************** I. Foundations 1. Organic Molecules and Chemical Bonding 2. Alkanes and Cycloalkanes 3. Haloalkanes

Reed, Christopher A.

282

A pulsed field gradient and NMR imaging investigations of the water retention mechanism by cellulose ethers in mortars  

SciTech Connect (OSTI)

The study presented in this paper is devoted to improve the knowledge on the influence of cellulose ethers (CE) on the freshly-mixed mortars water retention. Indeed, this crucial property is the most important imparted by these polysaccharides. One of the assumptions proposed to explain this phenomenon is that CE acts as diffusion barrier to the water. To test this hypothesis, the CE effect on the self-diffusion coefficient of water in solution and on the water mobility between two fresh cement pastes was studied by Nuclear Magnetic Resonance. CE does not significantly modify the water self-diffusion coefficient in CE solution or in admixed cement pastes. Moreover the interdiffusion imaging experiments demonstrated that the water diffusion at the paste/paste interface is not affected by the presence of cellulosic admixture.

Patural, Laetitia, E-mail: patural@emse.f [Ecole Nationale Superieure des Mines de Saint-Etienne, Centre SPIN, LPMG UMR 5148, 158 cours Fauriel, F-42023 Saint-Etienne Cedex 2 (France); Porion, Patrice [Centre de la Recherche sur la Matiere Divisee, CNRS-Universite d'Orleans, UMR 6619, 1b rue de la Ferollerie, F-45071 Orleans Cedex 2 (France); Van Damme, Henri [Laboratoire de Physico-chimie des Polymeres et Milieux Disperses, ESPCI ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 05 and Universite Paris Est - LCPC, 58 boulevard Lefebvre, 75732 Paris cedex 15 (France); Govin, Alexandre; Grosseau, Philippe [Ecole Nationale Superieure des Mines de Saint-Etienne, Centre SPIN, LPMG UMR 5148, 158 cours Fauriel, F-42023 Saint-Etienne Cedex 2 (France); Ruot, Bertrand; Deves, Olivier [Universite Paris-Est, Centre Scientifique et Technique du Batiment, Departement Enveloppe et Revetements/Division Enduits, Mortiers et Colles, 84 avenue Jean Jaures, F-77447 Marne-la-Vallee Cedex 2 (France)

2010-09-15T23:59:59.000Z

283

Characterization of the Deltaproteobacteria in contaminated and uncontaminated stream sediments and identification of potential mercury methylators  

SciTech Connect (OSTI)

Microbial communities were examined in surface stream sediments at 5 contaminated sites and 1 control site near Oak Ridge, TN, USA, to identify bacteria that could be contributing to mercury (Hg) methylation. The phylogenetic composition of the sediment bacterial community was examined over 3 quarterly sampling periods (36 samples) using 16S rRNA gene pyrosequencing. Only 3064 sequences (0.85% of the total community) were identified as Deltaproteobacteria, the only group known to methylate Hg, using the Ribosomal Database Project classifier at the 99% confidence threshold. Constrained ordination techniques indicated statistically significant positive linear correlations between Desulfobulbus spp., Desulfonema spp. and Desulfobacca spp. and methyl-Hg concentrations at the Hg-contaminated sites. In contrast, the distribution of organisms related to Byssovorax spp. was significantly correlated to inorganic carbon, nitrate and uranium concentrations but not to Hg or methyl-Hg. Overall, the abundance and richness of Deltaproteobacteria sequences were higher in uncontaminated sediments, while the majority of the members present at the contaminated sites were either known potential metal-reducers/methylators or metal tolerant species. Given the abundance relative to other known Hg methylators and the association with methyl-Hg, Desulfobulbus spp. is considered a prime candidate for involvement in Hg methylation in these streams.

Mosher, Jennifer [ORNL; Vishnivetskaya, Tatiana A [ORNL; Elias, Dwayne A [ORNL; Podar, Mircea [ORNL; Brooks, Scott C [ORNL; Brown, Steven D [ORNL; Brandt, Craig C [ORNL; Palumbo, Anthony Vito [ORNL

2012-01-01T23:59:59.000Z

284

Arsenic Methylation and Bladder Cancer Risk in CaseControl Studies in Argentina and the  

E-Print Network [OSTI]

Arsenic Methylation and Bladder Cancer Risk in Case­Control Studies in Argentina and the United's susceptibility to bladder cancer. Methods: Urinary methylation products were measured in subjects from Argentina (114 cases and 114 controls) and the United States (23 cases and 49 controls). Results: In Argentina

California at Berkeley, University of

285

et al. (2008) identified several additional methylation sites on FOXO1 that ap-  

E-Print Network [OSTI]

, it remains to be deter- mined how methylation alters the activity and posttranslational regulation. In this light, methylation could, therefore, play a very general role in the regulation of FOXO1 activity serve as a link between aging and age-related diseases such as diabe- tes and cancer. FOXO dysregulation

Hertel, Klemens J.

286

Mercury methylation in oxygen deficient zones of the oceans: No evidence for the predominance of anaerobes  

E-Print Network [OSTI]

Mercury methylation in oxygen deficient zones of the oceans: No evidence for the predominance Keywords: Methylmercury Oxygen minimum zone Arabian Sea Equatorial Eastern Pacific Mercury methylation Although a large fraction of the world's population is exposed to mercury through consumption of marine

Morel, François M. M.

287

Health risks associated with exposure to gasoline additives-methyl tertiary butyl ether [MTBE]. Hearing before a Subcommittee of the Committee on Appropriations, United States Senate, One Hundred Third Congress, First Session, Special Hearing  

SciTech Connect (OSTI)

This hearing focuses on an Alaskan study by the Centers for Disease Control which examines possible health risks associated with exposure to gasoline additive know as MTBE. Testimony is given by Dr. William Roper, Director, CDC.

Not Available

1993-01-01T23:59:59.000Z

288

Methyl-CpG island-associated genome signature tags  

DOE Patents [OSTI]

Disclosed is a method for analyzing the organismic complexity of a sample through analysis of the nucleic acid in the sample. In the disclosed method, through a series of steps, including digestion with a type II restriction enzyme, ligation of capture adapters and linkers and digestion with a type IIS restriction enzyme, genome signature tags are produced. The sequences of a statistically significant number of the signature tags are determined and the sequences are used to identify and quantify the organisms in the sample. Various embodiments of the invention described herein include methods for using single point genome signature tags to analyze the related families present in a sample, methods for analyzing sequences associated with hyper- and hypo-methylated CpG islands, methods for visualizing organismic complexity change in a sampling location over time and methods for generating the genome signature tag profile of a sample of fragmented DNA.

Dunn, John J

2014-05-20T23:59:59.000Z

289

THE JOURNAL OF CHEMICAL PHYSICS 138, 054301 (2013) Photodissociation dynamics of the methyl perthiyl radical at 248 nm  

E-Print Network [OSTI]

the photodissociation of the methyl perthiyl radical CH3SS at 248 nm. The radical was produced by flash pyrolysis

Neumark, Daniel M.

290

Optical measurements of methyl group tunneling in molecular crystals: Temperature dependence of the nuclear spin conversion rate  

E-Print Network [OSTI]

) The tunneling methyl groups in dimethyl-s-tetrazine (DMST) doped single crystals of durene were investigated

291

Modelling Study of the Low-Temperature Oxidation of Large Methyl Esters J. Biet, V. Warth, O. Herbinet*  

E-Print Network [OSTI]

-decane / methyl palmitate mixture in a jet-stirred reactor. This paper also presents the construction and a comparison of models for methyl esters from C7 up to C17 in terms of conversion in a jet-stirred reactor, the development of renewable energy is more vital than ever [1,2]. The production of biofuels such as methyl

Paris-Sud XI, Université de

292

Enol Ethers as Substrates for Efficient Z- and Enantioselective Ring-Opening/Cross-Metathesis Reactions Promoted by Stereogenic-at-Mo Complexes: Utility in Chemical Synthesis and Mechanistic Attributes  

E-Print Network [OSTI]

The first examples of catalytic enantioselective ring-opening/cross-metathesis (EROCM) reactions that involve enol ethers are reported. Specifically, we demonstrate that catalytic EROCM of several oxa- and azabicycles, ...

Yu, Miao

293

Endonuclease IV of Escherichia coli is induced by paraquat  

SciTech Connect (OSTI)

The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H/sub 2/O/sub 2/ produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, ..gamma.. rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate are known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusually sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O/sub 2/. The levels of endonuclease IV in uninduced or paraquat-treated cells were unaffected by mutations of oxyR, a H/sub 2/O/sub 2/-inducible gene that governs an oxidative-stress regulon. The results indicate that endonuclease IV is an inducible DNA-repair enzyme and that its induction can be mediated via the production of superoxide radicals.

Chan, E.; Weiss, B.

1987-05-01T23:59:59.000Z

294

MTBE Production Economics (Released in the STEO April 2001)  

Reports and Publications (EIA)

The purpose of this analysis is to evaluate the causes of methyl tertiary butyl ether (MTBE) price increases in 2000.

2001-01-01T23:59:59.000Z

295

Composition of the wax fraction of bitumen from methylated brown coals  

SciTech Connect (OSTI)

Changes in the group and individual compositions of the wax fractions of bitumen in the course of brown coal methylation were studied. With the use of IR and NMR spectroscopy and chromatography-mass spectrometry, it was found that the esters of methylated coal waxes consisted of the native esters of fatty acids and the methyl esters of these acids formed as a result of an alkylation treatment. Esterification and transesterification were predominant among the reactions of aliphatic fraction components. A positive effect of methanol alkylation on an increase in the yield of the aliphatic fractions was found.

S.I. Zherebtsov; A.I. Moiseev [Russian Academy of Sciences, Kemerovo (Russian Federation). Institute of Coal and Coal Chemistry

2009-04-15T23:59:59.000Z

296

Genomic DNA methylation in various developmental stages of two plant pathogenic fungi  

E-Print Network [OSTI]

blotting procedure. The blots were then hybridized with DNA probes from the highly repeated Neurospora crassa rDNA repeat unit labeled with [a. P] dCTP in a random-primed oligolabeling reaction. Results of the hybridizations were visualized... shows s. high degree of methylation at the inner (3') C in both stages (mycelia and sclerotia) at the genomic level. The rRNA genes exhibit the same high level of methylation at the 3' C with the addition of some stage specific methylation...

Schliesing, Laura Jo

1990-01-01T23:59:59.000Z

297

Solvent Effects on Metal Complexation with Crown Ethers from Liquid to Supercritical Fluids (DE-FG07-98ER 149 13)  

SciTech Connect (OSTI)

The purpose of this project is to study the salvation effects of metal-crown ether complexation in different solvents. It has been suggested in the literature that supercritical fluid carbon dioxide (SF-CO2) is a tunable solvent because its salvation environment can be varied with the fluid density. In this project, spectroscopic techniques including nuclear magnetic resonance (NMR) and Fourier Transform Infrared (FTIR) were used to evaluate salvation effects of metal crown complexation in organic solvents and in SF-CO2. In most solvent extraction systems, water is often involved in the extraction processes. We have carried out extensive studies of water-crown ether interactions in different solvents and in SF-CO2 using NMR and FTIR techniques. Water molecules can be attached to crown ethers through hydrogen bonding of H-0-H to the oxygen atoms of crown ether cavities. This type of interaction is like a Lewis acid-Lewis base complexation. During the course of this project, we noticed that some CO2 soluble Lewis base such as tri-n-butyl-phosphate (TBP) can also form such Lewis acid-Lewis base complexes with water and other inorganic acids including nitric acid and hydrochloric acid. Inorganic acids (e.g. nitric acid) are normally not soluble in SF-CO2. However, because TBP is highly soluble in SF-CO2, an inorganic acid bound to TBP via hydrogen bonding becomes CO2 soluble. This Lewis acid-Lewis base complex approach provides a method of introducing inorganic acids into supercritical fluid CO2 for chemical reactions.

Wai, C.M.

2002-06-01T23:59:59.000Z

298

Anti-inflammatory and antifibrotic effects of methyl palmitate  

SciTech Connect (OSTI)

Methyl palmitate (MP) has been shown earlier to inhibit Kupffer cells and rat peritoneal macrophages. To evaluate the potential of MP to inhibit the activation of other macrophages, RAW cells (macrophages of alveolar origin) were treated with varying concentrations of MP (0.25, 0.5, 1 mM). Assessment of cytotoxicity using MTT assay revealed that 0.25 and 0.5 mM are not toxic to RAW cells. MP was able to inhibit the phagocytic function of RAW cells. Treatment of cells with MP 24 hours prior to LPS stimulation significantly decreased nitric oxide release and altered the pattern of cytokines release; there was a significant decrease in TNF-{alpha} and a significant increase in IL-10 compared to the controls. However, there is a non-significant change in IL-6 level. Furthermore, phosphorylation of inhibitory kappa B (I{kappa}B{alpha}) protein was significantly decreased in RAW cells treated with 0.5 mM MP after LPS stimulation. Based upon the in-vitro results, it was examined whether MP treatment will be effective in preventing bleomycin-induced lung inflammation and fibrosis in-vivo. Bleomycin given by itself caused destruction of the lung architecture characterized by pulmonary fibrosis with collapse of air alveoli and emphysematous. Bleomycin induced a significant increase in hydroxyproline level and activated NF-{kappa}B, p65 expression in the lung. MP co-treatment significantly ameliorated bleomycin effects. These results suggest that MP has a potential of inhibiting macrophages in general. The present study demonstrated for the first time that MP has anti-inflammatory and antifibrotic effect that could be through NF-kB inhibition. Thus MP like molecule could be a promising anti-inflammatory and antifibrotic drug. - Research Highlights: >Methyl palmitate is a universal macrophage inhibitor. >It could be a promising nucleus of anti-inflammatory and antifibrotic drugs. >The underlying mechanism of these effects could be through NF-kB inhibition.

El-Demerdash, Ebtehal, E-mail: ebtehal_dm@yahoo.com

2011-08-01T23:59:59.000Z

299

Bioremediation of the organophosphate methyl parathion using genetically engineered and native organisms  

E-Print Network [OSTI]

to remediate hazardous substances at significantly higher rates than found with natural systems. Specifically, degradation of methyl parathion (MP) by hydrolysis with a genetically engineered Escherichia coli was investigated along with degradation of one...

Diaz Casas, Adriana Z.

2005-11-01T23:59:59.000Z

300

Thermomechanical properties of polyhedral oligomeric silsequioxane- poly(methyl methacrylate) nanocomposites  

E-Print Network [OSTI]

Poly(methyl methacrylate)s (PMMA) containing polyhedral oligomeric silsesquioxane (POSS) nanoparticles (d [approx.] 1.5 nm) were subjected to heological, mechanical, and morphological tests to determine the effects that ...

Kopesky, Edward Thomas

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

A unique regulatory phase of DNA methylation in the early mammalian embryo  

E-Print Network [OSTI]

DNA methylation is highly dynamic during mammalian embryogenesis. It is broadly accepted that the paternal genome is actively depleted of 5-methylcytosine at fertilization, followed by passive loss that reaches a minimum ...

Chan, Michelle M.

302

Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) in the Norwestern Atlantic  

E-Print Network [OSTI]

Halogenated 1'-methyl-1,2'-bipyrroles (MBPs) are a distinctive class of marine organic compounds. They are naturally produced, they have a unique carbon structure, they are highly halogenated, and they bioaccumulate in ...

Pangallo, Kristin C

2009-01-01T23:59:59.000Z

303

Temporal and spatial variation in methyl bromide emissions from a salt marsh   

E-Print Network [OSTI]

Methyl bromide (CH3Br) is a trace gas involved in stratospheric ozone depletion with both anthropogenic and natural sources. Estimates of natural source strengths are highly uncertain. In this study, >320 highly temporally ...

Drewer, Julia; Heal, Mathew R; Heal, Kate V; Smith, Keith A

2006-01-01T23:59:59.000Z

304

Toxicity of polychlorinated diphenyl ethers in hydra attenuata and in rat whole-embryo culture. Master's thesis  

SciTech Connect (OSTI)

Polychlorinated diphenyl ethers (PCDEs) are a class of biaryl compounds that have little commercial application, but appear to be widespread in the environment. They have been found in wood preservative waste dumpsites and in fly ash from municipal waste incinerators. They have been detected in bird eggs and tissues, fish, and other edible marine organisms in the United States, Canada, and Europe. There are limited reports in the extant literature on the toxicity of PCDEs. This study was designed to evaluate the toxicity of selected PCDEs in cultures of Hydra attenuata and post-implantation rat whole embryos. The toxicity of several closely related polychlorinated biphenyls (PCBs) was evaluated in both cultures and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was evaluated in whole embryo culture. Embryonic growth and development parameters (yolk sac diameter, crown-rump length, somite count, and DNA and protein content) and gross morphology were determined. Findings indicated that these chemicals were neither embryotoxic nor teratogenic. Thus, the PCDEs, which elicit other diverse toxic and biochemical responses in rodents, are relatively inactive in these bioassays for developmental toxicity.

Becker, M.C.

1991-05-01T23:59:59.000Z

305

Monodisperse porous polymer particles containing macrocyclic ether as a new class of sorbent for SR(II) separation  

SciTech Connect (OSTI)

Strontium{sup 90} is one of the typical fission products that may be found in high level liquid waste (HLLW). Separation of Sr{sup 90} prior to the vitrification is beneficial to the final treatment of solid radioactive waste. In this study, a new class of sorbent for Sr(II) was developed by loading the macrocyclic ether DtBuCH18C6 into the monodisperse porous polymer particles (MPPPs). The MPPPs are well-known as a promising chromatographic material due to the uniform particle size, porous morphology, good compatibility with organic extractants, and rigid matrix. The structure and micro-morphology of the sorbent particles were characterized. The adsorption behavior towards Sr(II) in HNO{sub 3} media was investigated by both batch and column experiments. High adsorption efficiency and selective separation of Sr(II) was obtained. The sorbent particles can be recycled for at least several times before obvious lose of the adsorption ability. This kind of sorbent possesses the potential to be used for strontium separation in radioactive liquid waste.

Leng, Yuxiao; Bai, Feifei [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Faculty of Chemical Science and Engineering, China University of Petroleum, Beijing 100084 (China); Ye, Gang; Wei, Jichao; Wang, Jianchen; Chen, Jing [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

2013-07-01T23:59:59.000Z

306

Investigation of HCCI Combustion of Diethyl Ether and Ethanol Mixtures Using Carbon 14 Tracing and Numerical Simulations  

SciTech Connect (OSTI)

Despite the rapid combustion typically experienced in Homogeneous Charge Compression Ignition (HCCI), components in fuel mixtures do not ignite in unison or burn equally. In our experiments and modeling of blends of diethyl ether (DEE) and ethanol (EtOH), the DEE led combustion and proceeded further toward completion, as indicated by {sup 14}C isotope tracing. A numerical model of HCCI combustion of DEE and EtOH mixtures supports the isotopic findings. Although both approaches lacked information on incompletely combusted intermediates plentiful in HCCI emissions, the numerical model and {sup 14}C tracing data agreed within the limitations of the single zone model. Despite the fact that DEE is more reactive than EtOH in HCCI engines, they are sufficiently similar that we did not observe a large elongation of energy release or significant reduction in inlet temperature required for light-off, both desired effects for the combustion event. This finding suggests that, in general, HCCI combustion of fuel blends may have preferential combustion of some of the blend components.

Mack, J H; Dibble, R W; Buchholz, B A; Flowers, D L

2004-01-16T23:59:59.000Z

307

Calcitriol inhibits Ether-a go-go potassium channel expression and cell proliferation in human breast cancer cells  

SciTech Connect (OSTI)

Antiproliferative actions of calcitriol have been shown to occur in many cell types; however, little is known regarding the molecular basis of this process in breast carcinoma. Ether-a-go-go (Eag1) potassium channels promote oncogenesis and are implicated in breast cancer cell proliferation. Since calcitriol displays antineoplastic effects while Eag1 promotes tumorigenesis, and both factors antagonically regulate cell cycle progression, we investigated a possible regulatory effect of calcitriol upon Eag1 as a mean to uncover new molecular events involved in the antiproliferative activity of this hormone in human breast tumor-derived cells. RT real-time PCR and immunocytochemistry showed that calcitriol suppressed Eag1 expression by a vitamin D receptor (VDR)-dependent mechanism. This effect was accompanied by inhibition of cell proliferation, which was potentiated by astemizole, a nonspecific Eag1 inhibitor. Immunohistochemistry and Western blot demonstrated that Eag1 and VDR abundance was higher in invasive-ductal carcinoma than in fibroadenoma, and immunoreactivity of both proteins was located in ductal epithelial cells. Our results provide evidence of a novel mechanism involved in the antiproliferative effects of calcitriol and highlight VDR as a cancer therapeutic target for breast cancer treatment and prevention.

Garcia-Becerra, Rocio [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico)] [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico); Diaz, Lorenza, E-mail: lorenzadiaz@gmail.com [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico)] [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico); Camacho, Javier [Department of Pharmacology, Centro de Investigacion y de Estudios Avanzados, Instituto Politecnico Nacional, Av. Instituto Politecnico Nacional 2508, San Pedro Zacatenco 07360, Mexico, D.F. (Mexico)] [Department of Pharmacology, Centro de Investigacion y de Estudios Avanzados, Instituto Politecnico Nacional, Av. Instituto Politecnico Nacional 2508, San Pedro Zacatenco 07360, Mexico, D.F. (Mexico); Barrera, David; Ordaz-Rosado, David; Morales, Angelica [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico)] [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico); Ortiz, Cindy Sharon [Department of Pathology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico)] [Department of Pathology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico); Avila, Euclides [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico)] [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico); Bargallo, Enrique [Department of Breast Tumors, Instituto Nacional de Cancerologia, Av. San Fernando No. 22, Tlalpan 14080, Mexico, D.F. (Mexico)] [Department of Breast Tumors, Instituto Nacional de Cancerologia, Av. San Fernando No. 22, Tlalpan 14080, Mexico, D.F. (Mexico); Arrecillas, Myrna [Department of Pathology, Instituto Nacional de Cancerologia, Av. San Fernando No. 22, Tlalpan 14080, Mexico, D.F. (Mexico)] [Department of Pathology, Instituto Nacional de Cancerologia, Av. San Fernando No. 22, Tlalpan 14080, Mexico, D.F. (Mexico); Halhali, Ali; Larrea, Fernando [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico)] [Department of Reproductive Biology, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Vasco de Quiroga No. 15, Tlalpan 14000 Mexico, D.F. (Mexico)

2010-02-01T23:59:59.000Z

308

An evaluation of the 3M Organic Vapor Monitor #3500 as a short term exposure limit sampling device for acetone, methyl ethyl ketone, and methyl iso butyl ketone  

E-Print Network [OSTI]

. An exploded view of the monitor is illustrated in Figure 1. The theory of diffusive sampling considers a concentration gra- dient between the ambient air and the adsorbent to be the driving force for sampling. For the adsorption to be controlled by diffu...AN EVALUATION OF THE 3M ORGANIC VAPOR MONITOR 43500 AS A SHOR'I TERM EXPOSURE LIMIT SAMPLING DEVICE FOR ACETONE, METHYL ETHYL KETONE, AND METHYL ISO BUTYL KETONE A Thesis by LLOYD B. ANDREW III Submitted to the Graduate College of Texas ASM...

Andrew, Lloyd B.

2012-06-07T23:59:59.000Z

309

Chromosome-wide mapping of DNA methylation patterns in normal and malignant prostate cells reveals pervasive methylation of gene-associated and conserved intergenic sequences  

E-Print Network [OSTI]

G island [13-15], chromosome-wide [15], or genome-wide [16] til- ing microarrays or to analyze by next generation sequen- cing [17,18]. Here, we describe the use of an MBD-chip approach (Figure 1A) to compare the chromosome-wide DNA methylation patterns... identified as differentially methylated in the LNCaP cells compared to the PrEC cells. We could then compare the distribution of CpG dinucleotide content and number of regions overlapping CpG islands in these simulated data sets with these parameters in our...

Yegnasubramanian, Srinivasan; Wu, Zhijin; Haffner, Michael C; Esopi, David; Aryee, Martin J; Badrinath, Raghav; He, Tony L; Morgan, James D; Carvalho, Benilton S; Zheng, Qizhi; De Marzo, Angelo M; Irizarry, Rafael A; Nelson, William G

2011-06-13T23:59:59.000Z

310

Radio-methyl vorozole and methods for making and using the same  

DOE Patents [OSTI]

Radiotracer vorozole compounds for in vivo and in vitro assaying, studying and imaging cytochrome P450 aromatase enzymes in humans, animals, and tissues and methods for making and using the same are provided. [N-radio-methyl] vorozole substantially separated from an N-3 radio-methyl isomer of vorozole is provided. Separation is accomplished through use of chromatography resins providing multiple mechanisms of selectivity.

Kim, Sung Won; Biegon, Anat; Fowler, Joanna S.

2014-08-05T23:59:59.000Z

311

Radio-methyl vorozole and methods for making and using the same  

DOE Patents [OSTI]

Radiotracer vorozole compounds for in vivo and in vitro assaying, studying and imaging cytochrome P450 aromatase enzymes in humans, animals, and tissues and methods for making and using the same are provided. [N-radio-methyl] vorozole substantially separated from an N-3 radio-methyl isomer of vorozole is provided. Separation is accomplished through use of chromatography resins providing multiple mechanisms of selectivity.

Kim, Sung Won; Biegon, Anat; Fowler, Joanna S.

2014-08-12T23:59:59.000Z

312

INVOLVED IN DE NOVO 2-containing complex involved in RNA-directed DNA methylation in Arabidopsis  

SciTech Connect (OSTI)

At least three pathways control maintenance of DNA cytosine methylation in Arabidopsis thaliana. However, the RNA-directed DNA methylation (RdDM) pathway is solely responsible for establishment of this silencing mark. We previously described INVOLVED IN DE NOVO 2 (IDN2) as being an RNA-binding RdDM component that is required for DNA methylation establishment. In this study, we describe the discovery of two partially redundant proteins that are paralogous to IDN2 and that form a stable complex with IDN2 in vivo. Null mutations in both genes, termed IDN2-LIKE 1 and IDN2-LIKE 2 (IDNL1 and IDNL2), result in a phenotype that mirrors, but does not further enhance, the idn2 mutant phenotype. Genetic analysis suggests that this complex acts in a step in the downstream portion of the RdDM pathway. We also have performed structural analysis showing that the IDN2 XS domain adopts an RNA recognition motif (RRM) fold. Finally, genome-wide DNA methylation and expression analysis confirms the placement of the IDN proteins in an RdDM pathway that affects DNA methylation and transcriptional control at many sites in the genome. Results from this study identify and describe two unique components of the RdDM machinery, adding to our understanding of DNA methylation control in the Arabidopsis genome.

Ausin, Israel; Greenberg, Maxim V.C.; Simanshu, Dhirendra K.; Hale, Christopher J.; Vashisht, Ajay A.; Simon, Stacey A.; Lee, Tzuu-fen; Feng, Suhua; Española, Sophia D.; Meyers, Blake C.; Wohlschlegel, James A.; Patel, Dinshaw J.; Jacobsen, Steven E. (UCLA); (MSKCC); (Delaware)

2012-10-23T23:59:59.000Z

313

Encapsulation and Characterization of Proton-Bound Amine Homodimers in a Water Soluble, Self-Assembled Supramolecular Host  

SciTech Connect (OSTI)

Cyclic amines can be encapsulated in a water-soluble self-assembled supramolecular host upon protonation. The hydrogen bonding ability of the cyclic amines, as well as the reduced degrees of rotational freedom, allows for the formation of proton-bound homodimers inside of the assembly which are otherwise not observable in aqueous solution. The generality of homodimer formation was explored with small N-alkyl aziridines, azetidines, pyrrolidines and piperidines. Proton-bound homodimer formation is observed for N-alkylaziridines (R = methyl, isopropyl, tert-butyl), N-alkylazetidines (R = isopropyl, tertbutyl), and N-methylpyrrolidine. At high concentration, formation of a proton-bound homotrimer is observed in the case of N-methylaziridine. The homodimers stay intact inside the assembly over a large concentration range, thereby suggesting cooperative encapsulation. Both G3(MP2)B3 and G3B3 calculations of the proton-bound homodimers were used to investigate the enthalpy of the hydrogen bond in the proton-bound homodimers and suggest that the enthalpic gain upon formation of the proton-bound homodimers may drive guest encapsulation.

Pluth, Michael; Fiedler, Dorothea; Mugridge, Jeffrey; Bergman, Robert; Raymond, Kenneth

2008-10-01T23:59:59.000Z

314

Polystyrene/Poly(methyl methacrylate) Blends in the Presence of Cyclohexane: Selective Solvent Washing or Equilibrium Adsorption?  

E-Print Network [OSTI]

-cyclohexane (PS:CH), poly(methyl methacrylate)-carbon tetrachloride (PMMA:CCl4), and PS:CCl4 adsorbing

315

Biogeochemistry of arsenic in natural waters: The importance of methylated species  

SciTech Connect (OSTI)

Water samples from a number of lakes and estuaries, mostly in California, showed measurable concentrations of methylated arsenic (equivalent to 1-59% of total As) with the exception of one highly alkaline lake. Neither depleted phosphate concentrations nor high dissolved salts correlated with the appearance of methylated forms of As. A temporal study of As speciation in Davis Creek Reservoir, a seasonally anoxic lake in northern California, demonstrated that dimethylarsinic acid increased sufficiently to become the dominant form of dissolved As within the surface photic zone during late summer and fall. Methylated forms decreased while arsenate increased when the lake over-turned in early December, which suggested a degradation of dimethylarsinic acid to arsenate.

Anderson, L.C.D.; Bruland, K.W. (Univ. of California, Santa Cruz (USA))

1991-03-01T23:59:59.000Z

316

Salt effect on the isobaric vapor-liquid equilibrium of the methyl acetate + methanol system  

SciTech Connect (OSTI)

The effect of sodium thiocyanate at constant salt mole fraction from 0.01 to 0.05 and at saturation on the vapor-liquid equilibrium (VLE) of methyl acetate + methanol has been studied at 101.32 kPa using a modified Othmer equilibrium still. The salt exhibited both salting-in and salting-out effects on the methyl acetate, the azeotrope being eliminated at saturation. The results were correlated using the extended UNIQUAC model of Sander et al. and the electrolytic NRTL model of Mock et al.

Iliuta, M.C.; Thyrion, F.C. [Louvain Univ., Louvain-la-Neuve (Belgium). Chemical Engineering Inst.] [Louvain Univ., Louvain-la-Neuve (Belgium). Chemical Engineering Inst.; Landauer, O.M. [Univ. Politehnica Bucharest (Romania)] [Univ. Politehnica Bucharest (Romania)

1996-07-01T23:59:59.000Z

317

Kinetics of the reduction of methyl viologen with hydrogen on a colloidal Pt catalyst  

SciTech Connect (OSTI)

The evolution of H/sub 2/ on a Pt catalyst under the influence of one-electron reductors is part of the photocatalytic process of decomposition of H/sub 2/O into H/sub 2/ and O/sub 2/. As a model reaction we selected the reduction of methyl viologen. The bonding constant for hydrogen on colloidal Pt, as well as the effective rate constant of the heterolytic splitting of H/sub 2/ on the same Pt catalyst are determined. A mathematical description of the reduction of methyl viologen with hydrogen is suggested.

Maier, V.E.; Shafirovich, V.Ya.

1988-10-01T23:59:59.000Z

318

Acute environmental toxicity and persistence of methyl salicylate: A chemical agent simulant. Final report  

SciTech Connect (OSTI)

The interactions of methyl salicylate with plant foliage and soils were assessed using aerosol/vapor exposure methods. Measurements of deposition velocity and residence times for soils and foliar surfaces are reported. Severe plant contact toxicity was observed at foliar mass-loading levels above 4 {mu}g/cm{sup 2} leaf; however, recovery was noted after four to fourteen days. Methyl salicylate has a short-term effect on soil dehydrogenase activity, but not phosphatase activity. Results of the earthworm bioassay indicated only minimal effects on survival.

Cataldo, D.A.; Ligotke, M.W.; Harvey, S.D.; Fellows, R.J.; Li, S.W.

1994-06-01T23:59:59.000Z

319

DEVELOPMENT OF ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS  

SciTech Connect (OSTI)

This Final Report for Cooperative Agreement No. DE-FC22-95PC93052, the ''Development of Alternative Fuels and Chemicals from Synthesis Gas,'' was prepared by Air Products and Chemicals, Inc. (Air Products), and covers activities from 29 December 1994 through 31 July 2002. The overall objectives of this program were to investigate potential technologies for the conversion of synthesis gas (syngas), a mixture primarily of hydrogen (H{sub 2}) and carbon monoxide (CO), to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at the LaPorte, Texas Alternative Fuels Development Unit (AFDU). Laboratory work was performed by Air Products and a variety of subcontractors, and focused on the study of the kinetics of production of methanol and dimethyl ether (DME) from syngas, the production of DME using the Liquid Phase Dimethyl Ether (LPDME{trademark}) Process, the conversion of DME to fuels and chemicals, and the production of other higher value products from syngas. Four operating campaigns were performed at the AFDU during the performance period. Tests of the Liquid Phase Methanol (LPMEOH{trademark}) Process and the LPDME{trademark} Process were made to confirm results from the laboratory program and to allow for the study of the hydrodynamics of the slurry bubble column reactor (SBCR) at a significant engineering scale. Two campaigns demonstrated the conversion of syngas to hydrocarbon products via the slurry-phase Fischer-Tropsch (F-T) process. Other topics that were studied within this program include the economics of production of methyl tert-butyl ether (MTBE), the identification of trace components in coal-derived syngas and the means to economically remove these species, and the study of systems for separation of wax from catalyst in the F-T process. The work performed under this Cooperative Agreement has continued to promote the development of technologies that use clean syngas produced from any one of a variety of sources (including coal) for the production of a spectrum of alternative fuels (hydrocarbons and oxygenate fuels), octane enhancers, and chemicals and chemical intermediates. In particular, the data from the 1995 LPMEOH{trademark} campaign provided confirmation of assumptions used in the design of the catalyst reduction system at the Kingsport LPMEOH{trademark} Commercial Demonstration Project, and the alternate methanol catalyst has been in use there since late 1998. The kinetic model was also expanded to allow for more accurate prediction of methanol production and carbon dioxide (CO{sub 2}) conversion, and more accurate modeling of by-product formation for the alternate methanol catalyst. The outstanding performance results of the LPMEOH{trademark} Process at Kingsport can be attributed in large part to the body of work performed since 1981 in collaboration between the U.S. Department of Energy (DOE) and Air Products. In addition, a pilot-plant-tested LPDME{trademark} Process has been demonstrated, and the product cost of DME from coal-derived syngas can be competitive in certain locations and applications. The need for liquid fuels will continue to be a critical concern for this nation in the 21st century. Efforts are needed to ensure the development and demonstration of economically competitive, efficient, environmentally responsible technologies that produce clean fuels and chemicals from coal under DOE's Vision 21 concept. These liquids will be a component of the fuel mix that will provide the transition from the current reliance on carbon-based fuels to the ultimate use of H{sub 2} as a means of energy transport. Indirect liquefaction, which converts the syngas (H{sub 2} and CO) produced by the gasification of coal to sulfur- and nitrogen-free liquid products, is a key component of the Vision 21 initiative. The results from this current program provide continued support to the objectives for the conversion of domestic coal to electric power and co-produced clean liquid fuels and chemicals in an environmentally superior manner.

Peter J. Tijrn

2003-05-31T23:59:59.000Z

320

Effect of Amino Acid Subsititution in Set1 on Histone H3 Methylation and Gene Silencing in Saaccharomyces Cerevisiae  

E-Print Network [OSTI]

EFFECT OF AMINO ACID SUBSITITUTION IN SET1 ON HISTONE H3 METHYLATION AND GENE SILENCING IN SAACCHAROMYCES CEREVISIAE A Senior Honors Thesis by MORGAN CHATEAU Submitted to the Office...3 Methylation and Gene Silencing in Saccharomyces cerevisiae (April 2008) Morgan Chateau Department of Biochemistry and Biophysics Texas A&M University Fellows Advisor: Associate Professor Dr. Mary Bryk Department of Biochemistry...

Chateau, Morgan

2008-08-24T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

The Action of Certain Acid Reagents on the Substituted Ureas  

E-Print Network [OSTI]

aniline and methyl phenyl urea chloride with pyridine - 6 Di-phenyl ethyl thio urea and phosgene with pyridine 7 Para mono brom di-phenyl thio urea and methyl phenyl urea chloride - 8 Di-phenyl thio urea and chlor formic ethyl ester with pyridine 9... Methyl ether of di-phenyl thio urea and methyl phenyl urea chloride with pyridine - - 10 Ethyl ether of ortho di-tolyl thio urea and methyl phenyl urea chloride 13 Ethyl ether of ortho di-tolyl thio urea and di-phenyl urea chloride 14 Methyl ether...

Brewster, Ray Q.

1915-01-01T23:59:59.000Z

322

Ethers help gasoline quality  

SciTech Connect (OSTI)

In this article three scenarios to evaluate the effect of etherification on gasoline production and quality are reviewed: Base case FCC/C{sub 4} alkylation complex - FCC unit operation for maximum gasoline yield, MTBE unit added to base case FCC unit operation and MTBE unit added to maximum olefins FCC unit operation. Details of the FCC, MTBE and C{sub 4} alkylation operations used in this article are reviewed, followed by a discussion of overall results.

Chang, E.J.; Leiby, S.M. (SRI International, Menlo Park, CA (US))

1992-02-01T23:59:59.000Z

323

Reverse Atom Transfer Radical Polymerization of Methyl Methacrylate in Room-Temperature Ionic Liquids  

E-Print Network [OSTI]

, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China Received 14, the removal and recycling of the catalytic materials become important. It is expected that using ionic liquids as ATRP media. They performed the copper(I)-mediated ATRP of methyl methacrylate (MMA) in 1-butyl-3

Wan, Xin-hua

324

Electronic structure calculations of radical reactions for poly(methyl methacrylate) degradation  

E-Print Network [OSTI]

exposed to UV light in low-Earth orbit (LEO) conditions experience degradation. Under LEO conditionsElectronic structure calculations of radical reactions for poly(methyl methacrylate) degradation to calculate the reaction energetics for decomposition reactions of radicals formed from UV radiation

325

Sequential 2 -O-Methylation of Archaeal Pre-tRNATrp Nucleotides  

E-Print Network [OSTI]

Sequential 2 -O-Methylation of Archaeal Pre-tRNATrp Nucleotides Is Guided by the Intron -O-methyla- tion of nucleotides C34 and U39 followed by intron exci- sion. Positioning of the box C proteins. With both kinetic studies and single nucleotide substitutions of target and guide nucleotides, we

Maxwell, E. Stuart

326

Selective Methylation Changes on the Bacillus subtilis Chemotaxis Receptor McpB Promote Adaptation*  

E-Print Network [OSTI]

. In the same background, McpB(E630D,E637D) produced methanol only upon aspara- gine addition, whereas McpB(Q371D,E630D) produced methanol only upon asparagine removal. Thus methanol release from Mcp, from which methanol is released in response to all stimuli. McpB has four putative methylation sites

Ordal, George W.

327

Infrared Study of the Molecular Orientation in Ultrathin Films of Behenic Acid Methyl Ester: Comparison between  

E-Print Network [OSTI]

Infrared Study of the Molecular Orientation in Ultrathin Films of Behenic Acid Methyl Ester-Blodgett transfer. The presence in the infrared spectra of several bands due to the methylene wagging and twisting and infrared spectroscopy have been developed to study these films. Infrared spectroscopy is particularly

Pezolet, Michel

328

Active transport, substrate specificity, and methylation of Hg(II) in anaerobic bacteria  

SciTech Connect (OSTI)

The formation of methylmercury (MeHg), which is biomagnified in aquatic food chains and poses a risk to human health, is effected by some iron- and sulfate-reducing bacteria (FeRB and SRB) in anaerobic environments. However, very little is known regarding the mechanism of uptake of inorganic Hg by these organisms, in part because of the inherent difficulty in measuring the intracellular Hg concentration. By using the FeRB Geobacter sulfurreducens and the SRB Desulfovibrio desulfuricans ND132 as model organisms, we demonstrate that Hg(II) uptake occurs by active transport. We also establish that Hg(II) uptake by G. sulfurreducens is highly dependent on the characteristics of the thiols that bind Hg(II) in the external medium, with some thiols promoting uptake and methylation and others inhibiting both. The Hg(II) uptake system of D. desulfuricans has a higher affinity than that of G. sulfurreducens and promotes Hg methylation in the presence of stronger complexing thiols. We observed a tight coupling between Hg methylation and MeHg export from the cell, suggesting that these two processes may serve to avoid the build up and toxicity of cellular Hg. Our results bring up the question of whether cellular Hg uptake is specific for Hg(II) or accidental, occurring via some essential metal importer. Our data also point at Hg(II) complexation by thiols as an important factor controlling Hg methylation in anaerobic environments.

Schasfer, Jeffra [Princeton University; Rocks, Sara [Princeton University; Zheng, Wang [ORNL; Liang, Liyuan [ORNL; Gu, Baohua [ORNL; Morel, Francois M [ORNL

2011-01-01T23:59:59.000Z

329

Biodegradation of triclosan and formation of methyl-triclosan in activated sludge under aerobic conditions  

E-Print Network [OSTI]

Biodegradation of triclosan and formation of methyl-triclosan in activated sludge under aerobic in activated sludge from a standard activated sludge WWTP equipped with enhanced biological phosphorus removal) and anaerobic conditions rather low removal rates were determined. In a laboratory-scale activated sludge

Kolaei, Alireza Rezania

330

Combustion chemical kinetics of biodiesel and related compounds (methyl and ethyl esters): Experiments and  

E-Print Network [OSTI]

1 Combustion chemical kinetics of biodiesel and related compounds (methyl and ethyl esters transportation fuel dedicated to the diesel engine, biodiesel, with an emphasis on ethyl esters because of biodiesel and related components, the main gaps in the field are highlighted to facilitate the convergence

Paris-Sud XI, Université de

331

Growth of diamond films using an enclosed methyl-acetylene and propadiene combustion flame  

E-Print Network [OSTI]

1 Growth of diamond films using an enclosed methyl-acetylene and propadiene combustion flame K Abstract Diamond growth in low pressure combustion flames was studied using a safer, more economical and chemical kinetic time scales in the combustion reactor. 1 Present Address: 3M Corporation, Bldg. 60-1N-01

Dandy, David

332

Methylation of Mercury by Bacteria Exposed to Dissolved, Nanoparticulate, and Microparticulate Mercuric Sulfides  

E-Print Network [OSTI]

Methylation of Mercury by Bacteria Exposed to Dissolved, Nanoparticulate, and Microparticulate in the environment is partly controlled by the bioavailability of inorganic divalent mercury (Hg(II)) to anaerobic matter to form chemical species that include organic-coated mercury sulfide nanoparticles as reaction

333

Neutralization of Methyl Cation via Chemical Reactions in Low-Energy Ion-Surface  

E-Print Network [OSTI]

with Fluorocarbon and Hydrocarbon Self-Assembled Monolayer Films A´ rpa´d Somogyi, Darrin L. Smith, and Vicki H-surface collisions of methyl cation at hydrocarbon and fluorocarbon self- assembled monolayer (SAM) surfaces produce with hydrocarbon and fluorocarbon SAMs occurs by concerted chemical reactions, i.e., that neutralization

Wysocki, Vicki H.

334

Spectroscopic investigation of the vibrational quasi-continuum arising from internal rotation of a methyl group  

SciTech Connect (OSTI)

The goal of this project is to use spectroscopic techniques to investigate in detail phenomena involving the vibrational quasi-continuum in a simple physical system. Acetaldehyde was chosen for the study because: (i) methyl groups have been suggested to be important promotors of intramolecular vibrational relaxation, (ii) the internal rotation of a methyl group is an easily describle large-amplitude motion, which should retain its simple character even at high levels of excitation, and (iii) the aldehyde carbonyl group offers the possibility of both vibrational and electronic probing. The present investigation of the ground electronic state has three parts: (1) understanding the {open_quotes}isolated{close_quotes} internal-rotation motion below, at, and above the top of the torsional barrier, (2) understanding in detail traditional (bond stretching and bending) vibrational fundamental and overtone states, and (3) understanding interactions involving states with multiquantum excitations of at least one of these two kinds of motion.

Hougen, J.T. [NIST, Gaithersburg, MD (United States)

1993-12-01T23:59:59.000Z

335

ALMA imaging study of methyl formate (HCOOCH$_{3}$) in the torsionally excited states towards Orion KL  

E-Print Network [OSTI]

We recently reported the first identification of rotational transitions of methyl formate (HCOOCH$_{3}$) in the second torsionally excited state toward Orion Kleinmann-Low (KL) observed with the Nobeyama 45 m telescope. In combination with the identified transitions of methyl formate in the ground state and the first torsional excited state, it was found that there is a difference in rotational temperature and vibrational temperature, where the latter is higher. In this study, high spatial resolution analysis by using Atacama Large Millimeter/Submillimeter Array (ALMA) science verification data was carried out to verify and understand this difference. Toward the Compact Ridge, two different velocity components at 7.3 and 9.1 km s$^{-1}$ were confirmed, while a single component at 7.3 km s$^{-1}$ was identified towards the Hot Core. The intensity maps in the ground, first, and second torsional excited states have quite similar distributions. Using extensive ALMA data, we determined the rotational and vibration...

Sakai, Yusuke; Hirota, Tomoya

2015-01-01T23:59:59.000Z

336

Experimental investigation of size effect on thermal conductivity for ultra-thin amorphous poly(methyl methacrylate) (PMMA) films  

E-Print Network [OSTI]

An investigation was conducted to determine whether a “size effect” phenomenon for one particular thermophysical property, thermal conductivity, actually exists for amorphous poly(methyl methacrylate) (PMMA) films with thicknesses ranging from 40 nm...

Kim, Ick Chan

2009-05-15T23:59:59.000Z

337

CORRELATION OF DNA METHYLATION WITH MERCURY CONTAMINATION IN MARINE ORGANISMS: A CASE STUDY OF NOAA MUSSEL WATCH TISSUE SAMPLES  

E-Print Network [OSTI]

American oysters (Crassostrea virginica) obtained from the NOAA Mussel Watch program were screened for DNA methylation, a type of epigenetic response to stressors. Oysters were collected from sites in the Gulf of Mexico having high mercury...

Brinkmeyer, Robin; Taylor, Robert; Germ, Kaylyn E.

2011-08-04T23:59:59.000Z

338

An assessment of methyl mercury and volatile mercury in land-applied sewage sludge  

SciTech Connect (OSTI)

In 1993, the US Environmental Protection Agency issued regulations covering the land-application of municipal sewage sludge. These regulations established maximum pollutant concentrations and were based upon a risk assessment of human exposure. Mercury, assumed to be inorganic and non-volatile, was one pollutant evaluated. From April, 1995 through February, 1996, the authors studied the species of mercury contaminating municipal sludge applied to land, and the potential for volatilization of mercury from land-applied sludge. Methyl mercury was found at 0.1% of total mercury concentrations and was emitted from land-applied sludge to the atmosphere. Elemental mercury (Hg) was formed in land-applied sludge via the reduction of oxidized mercury and was also emitted to the atmosphere. Hg emission from land-applied sludge was significantly elevated over background soil emission. Methyl mercury is more toxic and more highly bioaccumulated than inorganic mercury, and warrants assessment considering these special criteria. Additionally, mercury emission from sludge-amended soil may lead to the contamination of other environmental media with significant concentrations of the metal. Although these pathways were not evaluated in the regulatory risk assessment, they are an important consideration for evaluating the risks from mercury in land-applied sludge. This presentation will summarize the results of a re-assessment of US EPA regulations regarding the land-application of municipal sewage sludge using data on methyl mercury toxicity and mercury transport in the atmosphere.

Carpi, A. [Cornell Univ., Ithaca, NY (United States); Lindberg, S.E. [Oak Ridge National Lab., TN (United States)

1995-12-31T23:59:59.000Z

339

Arsenic methylation capability and hypertension risk in subjects living in arseniasis-hyperendemic areas in southwestern Taiwan  

SciTech Connect (OSTI)

Background: Cumulative arsenic exposure (CAE) from drinking water has been shown to be associated with hypertension in a dose-response pattern. This study further explored the association between arsenic methylation capability and hypertension risk among residents of arseniasis-hyperendemic areas in Taiwan considering the effect of CAE and other potential confounders. Method: There were 871 subjects (488 women and 383 men) and among them 372 were diagnosed as having hypertension based on a positive history or measured systolic blood pressure {>=} 140 mm Hg and/or diastolic blood pressure {>=} 90 mm Hg. Urinary arsenic species were determined by high-performance liquid chromatography-hydride generator and atomic absorption spectrometry. Primary arsenic methylation index [PMI, defined as monomethylarsonic acid (MMA{sup V}) divided by (As{sup III} + As{sup V})] and secondary arsenic methylation index (SMI, defined as dimethylarsinic acid divided by MMA{sup V}) were used as indicators for arsenic methylation capability. Results: The level of urinary arsenic was still significantly correlated with cumulative arsenic exposure (CAE) calculated from a questionnaire interview (p = 0.02) even after the residents stopped drinking the artesian well water for 2-3 decades. Hypertensive subjects had higher percentages of MMA{sup V} and lower SMI than subjects without hypertension. However, subjects having CAE > 0 mg/L-year had higher hypertension risk than those who had CAE = 0 mg/L-year disregard a high or low methylation index. Conclusion: Inefficient arsenic methylation ability may be related with hypertension risk.

Huang, Y.-K. [Graduate Institute of Medical Sciences, School of Medicine, Taipei Medical University, Taipei, Taiwan (China); Tseng, C.-H. [National Taiwan University College of Medicine, Taipei, Taiwan (China); Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan (China); Department of Medical Research and Development, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan (China); Huang, Y.-L. [Department of Public Health, School of Medicine, Taipei Medical University, No. 250 Wu-Hsing Street, Taipei 110, Taiwan (China); Yang, M.-H. [Department of Nuclear Science, National Tsing-Hua University, Hsinchu, Taiwan (China); Chen, C.-J. [Genomic Research Center, Academia Sinica, Taipei, Taiwan (China); Graduate Institute of Epidemiology, College of Public Health, National Taiwan University Taipei, Taiwan (China); Hsueh, Y.-M. [Department of Public Health, School of Medicine, Taipei Medical University, No. 250 Wu-Hsing Street, Taipei 110, Taiwan (China)]. E-mail: ymhsueh@tmu.edu.tw

2007-01-15T23:59:59.000Z

340

() Trichloromethane ()1,1,2,2-1,1,2,2-Tetrachloroethane  

E-Print Network [OSTI]

acetate () Ethylene glycol monobutyl ether () Ethylene glycol monomethy ether ()- O-dichlorobenzene ( ) Xylenes(o-,m-,p- isomers) () Cresol - 19 - #12;() Chlorobenzene () Amyl acetate () Isoamyl acetate () Isobutyl acetate () Isopropyl acetate () Ethyl acetate () Propyl acetate () Butyl acetate () Methyl acetate

Huang, Haimei

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

The Scientific Basis for the Regulation of Nanoparticles: Challenging Paracelsus and Pare  

E-Print Network [OSTI]

NANOTECHNOILOGY 402 (2007). 20. MTBE unquestionably causesTertiary-Butyl Ether (MTBE)-a Gasoline Additive-CausesMethyl Tertiary-butyl Ether (MTBE) in CD-I Mice and F-344

Goldstein, Bernard D.

2010-01-01T23:59:59.000Z

342

The interaction of organic adsorbate vibrations with substrate lattice waves in methyl-Si(111)-(1?×?1)  

SciTech Connect (OSTI)

A combined helium atom scattering and density functional perturbation theory study has been performed to elucidate the surface phonon dispersion relations for both the CH{sub 3}-Si(111)-(1?×?1) and CD{sub 3}-Si(111)-(1?×?1) surfaces. The combination of experimental and theoretical methods has allowed characterization of the interactions between the low energy vibrations of the adsorbate and the lattice waves of the underlying substrate, as well as characterization of the interactions between neighboring methyl groups, across the entire wavevector resolved vibrational energy spectrum of each system. The Rayleigh wave was found to hybridize with the surface rocking libration near the surface Brillouin zone edge at both the M{sup ¯}-point and K{sup ¯}-point. The calculations indicated that the range of possible energies for the potential barrier to the methyl rotation about the Si-C axis is sufficient to prevent the free rotation of the methyl groups at a room temperature interface. The density functional perturbation theory calculations revealed several other surface phonons that experienced mode-splitting arising from the mutual interaction of adjacent methyl groups. The theory identified a Lucas pair that exists just below the silicon optical bands. For both the CH{sub 3}- and CD{sub 3}-terminated Si(111) surfaces, the deformations of the methyl groups were examined and compared to previous experimental and theoretical work on the nature of the surface vibrations. The calculations indicated a splitting of the asymmetric deformation of the methyl group near the zone edges due to steric interactions of adjacent methyl groups. The observed shifts in vibrational energies of the -CD{sub 3} groups were consistent with the expected effect of isotopic substitution in this system.

Brown, Ryan D.; Hund, Zachary M.; Sibener, S. J., E-mail: s-sibener@uchicago.edu [The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637 (United States); Campi, Davide; Bernasconi, M. [Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); O’Leary, Leslie E.; Lewis, Nathan S. [Beckman Institute and Kavli Nanoscience Institute, Division of Chemistry and Chemical Engineering, 210 Noyes Laboratory, 127-72, California Institute of Technology, Pasadena, California 91125 (United States); Benedek, G. [Dipartimento di Scienza dei Materiali, Universitá di Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Donostia International Physics Center (DIPC), Universidad del País Vasco (EHU), 20018 Donostia / San Sebastian (Spain)

2014-07-14T23:59:59.000Z

343

Electrochemical investigation of the energetics of particulate titanium dioxide photocatalysts. The methyl viologen-acetate system  

SciTech Connect (OSTI)

Addition of methyl viologen (MV/sup 2 +/) enhances the anodic currents observed for TiO/sub 2/ suspensions under illumination by trapping of photogenerated electrons with formation of MV/sup +/. The magnitude of the photocurrent depends upon the relative location of the semiconductor Fermi level and E/sub redox/ of the MV/sup 2 +//MV/sup +/.couple. The location of the Fermi level in the anatase powders was estimated as -0.05 V vs. NHE (pH 0) based on the observed variation of photocurrent with pH. The shift in the quasi-Fermi level with light intensity is also discussed.

Ward, M.D.; White, J.R.; Bard, A.J.

1983-01-12T23:59:59.000Z

344

Storage effects on desorption efficiencies of methyl ethyl ketone and styrene collected on activated charcoal  

E-Print Network [OSTI]

in the worker ' s breathir ng zone cont ir uously during his working day. Solid ad- sorbents are used almost exclusively I' or this type of sampling. Among the marr, adsorbents avail able (s ! i ca gel, activated alumina, Tenax, etc. } acti&!ated charcoa&1 I... efficier&cy nf methyl etiiy', Ketone and styrene monomer adsorbed on activated charcoal samples, and stored under isotherm&al condit'ions, were investigated as a function of storage time. The dependence of the storage time effects on the storage temp...

Dommer, Richard Alvin

1978-01-01T23:59:59.000Z

345

A circadian rhythm in the susceptibility of the boll weevil, Anthonomus grandis Boheman to methyl parathion  

E-Print Network [OSTI]

and for his assistance in the preparation of the manuscript. Apprecia tion is also extended to Dr. J. C. Gaines, Dr. R. L. Hanna, Mr. N. M. Randolph, and Dr. R. D. Staten for their suggestions and criticisms in the preparation of this manuscript. TABLE...:14, decapitated and then held in LL for 10 days. (D) Held in LD 10:14 for 10 days, decapitated and then held for 10 more days in LD 10:14 LD 50 values obtained from topical appli- cations of methyl parathion to boll weevlls at various times of day'. The LD...

Cole, Charles L

1967-01-01T23:59:59.000Z

346

Thiophanate-methyl, persistence in soybeans and effects on yield, seed quality, emergence and nodulation  

E-Print Network [OSTI]

containing natural rhizobia populations. Persistence of the fungitoxic TM product, methyl-2-benzimidazole- carbamate (MBC) in/on soybeans was determined spectrophotometrically after once and twice spraying TM (1. 10 kg/ha a. i. ). In once-sprayed tissues... planting. Efficac of TM as a foliar fun icide. Untreated Bragg and Coker 338 soybeans were planted as above. When pods reached 1-2 cm length (Sept. 21), the soybeans were sprayed with TM (Topsin-M 70 WP) at 1. 10 kg/ha a. i. and again 18 days later...

Lyons, Philip Christopher

1981-01-01T23:59:59.000Z

347

Combined 3D-QSAR, molecular docking and molecular dynamics study on thyroid hormone activity of hydroxylated polybrominated diphenyl ethers to thyroid receptors ?  

SciTech Connect (OSTI)

Several recent reports suggested that hydroxylated polybrominated diphenyl ethers (HO-PBDEs) may disturb thyroid hormone homeostasis. To illuminate the structural features for thyroid hormone activity of HO-PBDEs and the binding mode between HO-PBDEs and thyroid hormone receptor (TR), the hormone activity of a series of HO-PBDEs to thyroid receptors ? was studied based on the combination of 3D-QSAR, molecular docking, and molecular dynamics (MD) methods. The ligand- and receptor-based 3D-QSAR models were obtained using Comparative Molecular Similarity Index Analysis (CoMSIA) method. The optimum CoMSIA model with region focusing yielded satisfactory statistical results: leave-one-out cross-validation correlation coefficient (q{sup 2}) was 0.571 and non-cross-validation correlation coefficient (r{sup 2}) was 0.951. Furthermore, the results of internal validation such as bootstrapping, leave-many-out cross-validation, and progressive scrambling as well as external validation indicated the rationality and good predictive ability of the best model. In addition, molecular docking elucidated the conformations of compounds and key amino acid residues at the docking pocket, MD simulation further determined the binding process and validated the rationality of docking results. -- Highlights: ? The thyroid hormone activities of HO-PBDEs were studied by 3D-QSAR. ? The binding modes between HO-PBDEs and TR? were explored. ? 3D-QSAR, molecular docking, and molecular dynamics (MD) methods were performed.

Li, Xiaolin [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Ye, Li [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China)] [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China); Wang, Xiaoxiang [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Wang, Xinzhou [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China)] [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China); Liu, Hongling [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China); Zhu, Yongliang [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China)] [Suzhou NeuPharma Co.,Ltd, Suzhou 215123 (China); Yu, Hongxia, E-mail: hongxiayu01@yahoo.com.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)] [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046 (China)

2012-12-15T23:59:59.000Z

348

In-cylinder pressure characteristics of a CI engine using blends of diesel fuel and methyl esters of beef tallow  

SciTech Connect (OSTI)

A Cummins N14-410 diesel engine was operated on 12 fuels produced by blending methyl tallowate, methyl soyate, and ethanol with no. 2 diesel fuel. Engine in-cylinder pressure data were used to evaluate engine performance. Peak cylinder pressures for each fuel blend at all engine speeds were lower than peak pressure for diesel fuel with the exception of the 80% diesel, 13% methyl tallowate, and 7% ethanol; and the 80% diesel, 6.5% methyl tallowate, 6.5% methyl soyate and 7% ethanol blends. The indicated mean effective pressure (IMEP) values for all fuel blends were less than for diesel fuel. The differences in IMEP values correlated with differences in power output of the engine. Similarly, maximum rates of pressure rise for most fuel blends were less than for diesel fuel. It was concluded that the fuel blends used in this study would have no detrimental long-term effects on engine performance, wear, and knock. 6 refs., 4 figs., 7 tabs.

Ali, Y.; Hanna, M.A.; Borg, J.E. [Univ. of Nebraska, Lincoln, NE (United States)

1996-05-01T23:59:59.000Z

349

Characterization of the Deltaproteobacteria in Contaminated and Uncontaminated Surface Stream Sediments and Identification of Potential Mercury Methylators  

SciTech Connect (OSTI)

Microbial communities were examined in surface stream sediments at five contaminated sites and one control site near Oak Ridge, TN in order to identify bacteria that could be contributing to mercury methylation. The phylogenetic composition of the sediment bacterial community was examined over three quarterly sampling periods (36 samples) using 16s rRNA pyrosequencing. Only 3064 sequences (0.85 % of the total community) were identified as Deltaproteobacteria by the RDP classifier at the 99% confidence threshold. Constrained ordination techniques indicated significant positive correlations between Desulfobulbus spp., Desulfonema spp. and Desulfobacca spp. and methyl mercury concentrations in the contaminated sites. On the contrary, the distribution of organisms related to Byssovorax was significantly correlated to inorganic carbon, nitrate and uranium concentrations. Overall, the abundance and richness of Deltaproteobacteria sequences were higher in the sediments of the site, while the majority of the members present at the contaminated sites were either known metal reducers/methylators or metal tolerant species.

Mosher, Jennifer J [ORNL; Vishnivetskaya, Tatiana A [ORNL; Elias, Dwayne A [ORNL; Podar, Mircea [ORNL; Brooks, Scott C [ORNL; Brown, Steven D [ORNL; Brandt, Craig C [ORNL; Palumbo, Anthony Vito [ORNL

2012-01-01T23:59:59.000Z

350

Multiple Objective Stormwater Management For the Coliseum Complex  

E-Print Network [OSTI]

methyl tertiary butyl ether (MTBE) remain in the soil around5.2 ppb xylenes, and 160 ppb MTBE remain in the groundwater

Jones, Jesse; Kraai, Rachel

2009-01-01T23:59:59.000Z

351

Energy Efficiency Improvement and Cost Saving Opportunities for the Petrochemical Industry - An ENERGY STAR(R) Guide for Energy and Plant Managers  

E-Print Network [OSTI]

Ethylene dichloride 1 MTBE 2 Vinylchloride 3 Ethylbenzene 1Methyl- Tertiary-Butyl-Ether (MTBE) or Ethyl-Tertiary-Butyl-Styrene Vinylchloride MTBE Benzene, Toluene, Xylene Acetone

Neelis, Maarten

2008-01-01T23:59:59.000Z

352

A Solid-State NMR Study of Tungsten Methyl Group Dynamics in [W(5-C5Me5)Me4][PF6  

E-Print Network [OSTI]

A Solid-State NMR Study of Tungsten Methyl Group Dynamics in [W(5-C5Me5)Me4][PF6] Douglas C. Maus Spinning (MAS) 13C and static 2H NMR studies of the dynamics of the methyl groups coordinated to tungsten

Griffin, Robert G.

353

Long-Range Ferromagnetic Ordering in Two-Dimensional Coordination Polymers Co[N(CN)2]2(L) [L ) Pyrazine Dioxide (pzdo) and 2-Methyl  

E-Print Network [OSTI]

) Pyrazine Dioxide (pzdo) and 2-Methyl Pyrazine Dioxide (mpdo)] with Dual µ- and µ3-[N(CN)2] Bridges Hao by the addition of ancillary ligands of pyrazine dioxide (pzdo) and 2-methyl pyrazine dioxide (mpdo) into the Co]- , possesses three coordination nitrogen atoms and several possible coordination modes: terminal, bidentate 1

Gao, Song

354

Cytoprotective Effects of Dietary Fatty Acids on Oxidative Stress in Hepatocytes  

E-Print Network [OSTI]

common dietary fatty acids to subsequent inflammation and stress. Hepatocytes (HepG2 cell line) were treated with oleic, linoleic and palmitic acid at different concentrations and exposed to the pro-oxidant tert-butyl hydroperoxide (t-BHP) to induce...

Richardson, Thomas C

2012-07-11T23:59:59.000Z

355

JOURNALDE PHYSIQUEIV ColloqueC8, supplbmentau Journal de Physique I, Volume 3,dicembre1993  

E-Print Network [OSTI]

-Telechelic Polymers (HTP) has been prepared. Prelerninary SAXS results on a,w - carboxy poly (tert. butyl acrylate patterns. A new class of model ionomers has been developed in Liege: the Halato-Telechelic Polymers. HTP and discussion All the experimentsperformed until now confirm the multi-peak structure of the new HTP's at low

Boyer, Edmond

356

Isomerization of methyl linoleate on ruthenium(III) alkoxide complex; Mathematical modeling  

SciTech Connect (OSTI)

The isomerization of methyl linoleate using ruthenium alkoxide complexes is described. With alcohols, such as isopropyl alcohol (IPA), 1-butanol, 1-hexanol, and 1-octanol, isomerization of double bonds to produce a conjugated system is the main reaction, with hydrogenation being the side reaction. The latter is formed via the conjugated product. Based on kinetic and infrared spectroscopic data, it is concluded that the active catalytic species is a ruthenium hydride complex formed by the decomposition of the unstable alkoxide. The reaction is mathematically modeled, and the rate parameters are obtained by fitting the simulation to experimental data. These values are compared with data obtained from reactions carried out with supported ruthenium-nickel heterogeneous catalyst.

Mukesh, D.; Narasimhan, C.S.; Ramnarayan, K.; Deshpande, V.M

1989-08-01T23:59:59.000Z

357

Embedded Piezoresistive Microcantilever Sensors Functionalized for the Detection of Methyl Salicylate  

SciTech Connect (OSTI)

Sensors designed to detect the presence of methyl salicylate (MeS) have been tested. These sensors use a sensor platform based on the embedded piezoresistive microcantilever (EPM) design. Sensing materials tested in this study included the polymer poly (ethylene vinyl acetate), or PEVA as well as a composite sensing material consisting of the enzyme SA-binding protein 2, or SABP-2. The SABP-2 was immobilized within a biocompatible Hypol gel matrix. The PEVA-based sensors exhibited slower but reversible responses to MeS vapors, recovering fully to their initial state after the analyte was removed. SABP-2 sensors exhibited faster overall response to the introduction of MeS, responding nearly instantly. These sensors, however, do not recover after exposures have ended. Sensors using the SABP-2 sensing materials act instead as integrating sensors, measuring irreversibly the total MeS dose obtained.

Porter, T. L. [UNLV; Venedam, R. J. [NSTec

2013-03-01T23:59:59.000Z

358

Methyl Chloride from Direct Methane Partial Oxidation: A High-Temperature Shilov-Like Catalytic System  

SciTech Connect (OSTI)

The intention of this study is to demonstrate and evaluate the scientific and economic feasibility of using special solvents to improve the thermal stability of Pt-catalyst in the Shilov system, such that a high reaction temperature could be achieved. The higher conversion rate (near 100%) of methyl chloride from partial oxidation of methane under the high temperature ({approx} 200 C) without significant Pt0 precipitation has been achieved. High concentration of the Cl- ion has been identified as the key for the stabilization of the Pt-catalysts. H/D exchange measurements indicated that the over oxidation will occur at the elevated temperature, developments of the effective product separation processes will be necessary in order to rationalize the industry-visible CH4 to CH3Cl conversion.

Yongchun Tang; John (Qisheng) Ma

2012-03-23T23:59:59.000Z

359

Liquid-liquid equilibria of the ternary system water + acetic acid + 2-methyl-2-butanol  

SciTech Connect (OSTI)

Liquid-liquid equilibria for the ternary system water + acetic acid + 2-methyl-2-butanol were measured over a temperature range of (288 to 323) K. The results were used to estimate the interaction parameters between each of the three compounds for the NRTL and UNIQUAC models and between each of the main groups of H{sub 2}O, CH{sub 2} (paraffinic CH{sub 2}), OH, and COOH for the UJNIFAC model as a function of temperature. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the three models. The NRTL equation was the most accurate model in correlating the overall equilibrium compositions of the studied system. The UNIFAC model satisfactorily predicted the equilibrium compositions.

Fahim, M.A.; Al-Muhtaseb, S.A. [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering] [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

1996-11-01T23:59:59.000Z

360

Homogeneous Hydrogenation of CO2 to Methyl Formate Utilizing Switchable Ionic Liquids  

SciTech Connect (OSTI)

Capture of CO2 and subsequent hydrogenation allows for base/alcohol-catalyzed conversion of CO2 to methylformate in one pot. The conversion of CO2 proceeds via alkylcarbonates, to formate salts and then formate esters, which can be catalyzed by base and alcohol with the only byproduct being water. The system operates at mild conditions (300 psi H2, 140 ?C). Reactivity is strongly influenced by temperature and choice of solvent. In the presence of excess of base (DBU) formate is predominant product while in excess of methanol methyl formate is major product. 110 ?C yields formate salts, 140 ?C promotes methylformate. The authors acknowledge internal Laboratory Directed Re-search and Development (LDRD) funding from Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for the U.S. Department of Energy.

Yadav, Mahendra (ORCID:0000000202660382); Linehan, John C.; Karkamkar, Abhijeet J.; Van Der Eide, Edwin F.; Heldebrant, David J.

2014-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Interactions in 1-ethyl-3-methyl imidazolium tetracyanoborate ion pair: Spectroscopic and density functional study  

SciTech Connect (OSTI)

Density Functional Theory is used to investigate a weakly coordinating room-temperature ionic liquid, 1-ethyl-3-methyl imidazolium tetracyanoborate ([Emim]{sup +}[TCB]{sup -}). Four locally stable conformers of the ion pair were located. Atoms-in-molecules (AIM) and electron density analysis indicated the existence of several hydrogen bonds. Further investigation through the Natural Bond Orbital (NBO) and Natural Energy Decomposition Analysis (NEDA) calculations provided insight into the origin of interactions in the [Emim]{sup +}[TCB]{sup -} ion pair. Strength of molecular interactions in the ionic liquid was correlated with frequency shifts of the characteristic vibrations of the ion pair. Harmonic vibrations of the ion pair were also compared with the experimental Raman and Infrared spectra. Vibrational frequencies were assigned by visualizing displacements of atoms around their equilibrium positions and through Potential Energy Distribution (PED) analysis.

Mao, James X.; Lee, Anita S.; Kitchin, John R.; Nulwala, Hunaid B; Luebke, David R.; Damodaran, Krishnan

2013-04-24T23:59:59.000Z

362

Free Radical Polymerization of Styrene and Methyl Methacrylate in Various Room Temperature Ionic Liquids  

SciTech Connect (OSTI)

Conventional free radical polymerization of styrene and methyl methacrylate was carried out in various room temperature ionic liquids (RTILs). The RTILs used in this research encompass a wide range of cations and anions. Typical cations include imidazolium, phosphonium, pyridinium, and pyrrolidinium; typical anions include amide, borate, chloride, imide, phosphate, and phosphinate. Reactions are faster and polymers obtained usually have higher molecular weights when compared to polymerizations carried out in volatile organic solvents under the same conditions. This shows that rapid rates of polymerization and high molecular weights are general features of conventional radical polymerizations in RTILs. Attempts to correlate the polarities and viscosities of the RTILs with the polymerization behavior fail to yield discernible trends.

Zhang, Hongwei [University of Tennessee, Knoxville (UTK); Hong, Kunlun [ORNL; Mays, Jimmy [ORNL

2005-01-01T23:59:59.000Z

363

Transparent Poly(methyl methacrylate)/Single-Walled Carbon Nanotube (PMMA/SWNT) Composite Films with Increased  

E-Print Network [OSTI]

Transparent Poly(methyl methacrylate)/Single-Walled Carbon Nanotube (PMMA/SWNT) Composite Films to conventional polymer composites due to the stronger interac- tions between polymer and filler phases. Carbon and fast-growing class of materials with nanosized filler domains finely dispersed in a polymer matrix.[1

Harmon, Julie P.

364

MODELING FRETTING-CORROSION WEAR OF 316L SS AGAINST POLY(METHYL METHACRYLATE) WITH THE POINT DEFECT  

E-Print Network [OSTI]

1 MODELING FRETTING-CORROSION WEAR OF 316L SS AGAINST POLY(METHYL METHACRYLATE) WITH THE POINT; ddm2@psu.edu c Center of Research Excellence in Corrosion Research Institute King Fahd University at investigating experimentally fretting corrosion, that is, corrosion induced by friction of AISI 316L SS against

Boyer, Edmond

365

270 | VOL.9 NO.3 | MARCH2012 | nature methods Key requirements for methylation analysis of large sample sizes  

E-Print Network [OSTI]

). This method eliminates five steps from Illumina's library- construction protocol such that multiplexed and sequenced all at once in a single Illumina HiSeq flowcell. Additionally we designed barcodes to process 384 an analysis pipeline for read mapping and methylation quantification, called bisReadMapper (Supplementary Fig

Cai, Long

366

Understanding mercury demethylation is the key to decrease the high environmental levels of the neurotoxin methyl-Hg in lakes.  

E-Print Network [OSTI]

dynamics of MeHg is the net result of three major processes: 1) formation by Hg methylation 2) degradation (demethylation) and Hg2+ reduction to Hg0 and evasion to the atmosphere. The major process of MeHg degradation is driven by UV light in surface waters. Although biotic demethylation processes are less well understood

Uppsala Universitet

367

Mercury Methylation at Mercury Mines In The Humboldt River Basin, Nevada, USA  

SciTech Connect (OSTI)

Total Hg and methylmercury concentrations were measured in mine-waste calcines (retorted ore), sediment, and water samples collected in and around abandoned mercury mines in western Nevada to evaluate Hg methylation at the mines and in the Humboldt River basin. Mine-waste calcines contain total Hg concentrations as high as 14 000?g/g. Stream-sediment samples collected within 1 km of the mercury mines contain total Hg concentrations as high as 170?g/g, whereas stream sediments collected>5 km from the mines, and those collected from the Humboldt River and regional baseline sites, contain total Hg concentrations<0.5?g/g. Similarly, methylmercury concentrations in mine-waste calcines are locally as high as 96 ng/g, but methylmercury contents in stream-sediments collected downstream from the mines and from the Humboldt River are lower, ranging from<0.05 to 0.95 ng/g. Stream-water samples collected below two mines studied contain total Hg concentrations ranging from 6 to 2000 ng/L, whereas total Hg in Humboldt River water was generally lower ranging from 2.1 to 9.0 ng/L. Methylmercury concentrations in the Humboldt River water were the lowest in this study (<0.02-0.27 ng/L). Although total Hg and methylmercury concentrations are locally high in mine-waste calcines, there is significant dilution of Hg and lower Hg methylation down gradient from the mines, especially in the sediments and water collected from the Humboldt River, which is> 8 km from any mercury mines. Our data indicate little transference of Hg and methylmercury from the sediment to the water column due to the lack of mine runoff in this desert climate.

Gray, John E. (U.S. Geological Survey); Crock, James G. (U.S. Geological Survey); Lasorsa, Brenda K. (BATTELLE (PACIFIC NW LAB))

2002-12-01T23:59:59.000Z

368

Insights antifibrotic mechanism of methyl palmitate: Impact on nuclear factor kappa B and proinflammatory cytokines  

SciTech Connect (OSTI)

Fibrosis accompanies most chronic liver disorders and is a major factor contributing to hepatic failure. Therefore, the need for an effective treatment is evident. The present study was designed to assess the potential antifibrotic effect of MP and whether MP can attenuate the severity of oxidative stress and inflammatory response in chronic liver injury. Male albino rats were treated with either CCl{sub 4} (1 ml/kg, twice a week) and/or MP (300 mg/kg, three times a week) for six weeks. CCl{sub 4}-intoxication significantly increased liver weight, serum aminotransferases, total cholesterol and triglycerides while decreased albumin level and these effects were prevented by co-treatment with MP. As indicators of oxidative stress, CCl{sub 4}-intoxication caused significant glutathione depletion and lipid peroxidation while MP co-treatment preserved them within normal values. As markers of fibrosis, hydroxyproline content and ?-SMA expression increased markedly in the CCl{sub 4} group and MP prevented these alterations. Histopathological examination by both light and electron microscope further confirmed the protective efficacy of MP. To elucidate the antifibrotic mechanisms of MP, the expression of NF-?B, iNOS and COX-2 and the tissue levels of TNF-? and nitric oxide were assessed; CCl{sub 4} increased the expression of NF-?B and all downstream inflammatory cascade while MP co-treatment inhibited them. Collectively these findings indicate that MP possesses a potent antifibrotic effect which may be partly a consequence of its antioxidant and anti-inflammatory properties. -- Highlights: ? Methyl palmitate is free fatty acid methyl ester. ? It possesses a strong antifibrotic effect. ? It inhibits NF-?B and the consequent proinflammatory and oxidative stress response.

Mantawy, Eman M.; Tadros, Mariane G. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)] [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt); Awad, Azza S. [Department of Pharmacology and Toxicology, Faulty of Pharmacy, Al-Azhar University, Cairo (Egypt)] [Department of Pharmacology and Toxicology, Faulty of Pharmacy, Al-Azhar University, Cairo (Egypt); Hassan, Dina A.A. [Department of Histology, Faculty of Medicine, Al-Azhar University, Cairo (Egypt)] [Department of Histology, Faculty of Medicine, Al-Azhar University, Cairo (Egypt); El-Demerdash, Ebtehal, E-mail: ebtehal_dm@yahoo.com [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)] [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)

2012-01-01T23:59:59.000Z

369

Polybrominated diphenyl ethers in e-waste: Level and transfer in a typical e-waste recycling site in Shanghai, Eastern China  

SciTech Connect (OSTI)

Highlights: • PBDEs were detected in the majority of e-waste. • PBDEs were found in TVs made in China after 1990. • The levels of ?PBDEs in e-waste made in Japan far exceed the threshold limit of RoHS. • The inappropriate recycling and disposal of e-waste is an important source of PBDEs. - Abstract: Very few data for polybrominated diphenyl ethers (PBDEs) were available in the electronic waste (e-waste) as one of the most PBDEs emission source. This study reported concentrations of PBDEs in e-waste including printer, rice cooker, computer monitor, TV, electric iron and water dispenser, as well as dust from e-waste, e-waste dismantling workshop and surface soil from inside and outside of an e-waste recycling plant in Shanghai, Eastern China. The results showed that PBDEs were detected in the majority of e-waste, and the concentrations of ?PBDEs ranged from not detected to 175 g/kg, with a mean value of 10.8 g/kg. PBDEs were found in TVs made in China after 1990. The mean concentrations of ?PBDEs in e-waste made in Korea, Japan, Singapore and China were 1.84 g/kg, 20.5 g/kg, 0.91 g/kg, 4.48 g/kg, respectively. The levels of ?PBDEs in e-waste made in Japan far exceed the threshold limit of RoHS (1.00 g/kg). BDE-209 dominated in e-waste, accounting for over 93%. The compositional patterns of PBDEs congeners resembled the profile of Saytex 102E, indicating the source of deca-BDE. Among the samples of dust and surface soil from a typical e-waste recycling site, the highest concentrations of ?{sub 18}PBDEs and BDE-209 were found in dust in e-waste, ranging from 1960 to 340,710 ng/g and from 910 to 320,400 ng/g, which were 1–2 orders of magnitude higher than other samples. It suggested that PBDEs released from e-waste via dust, and then transferred to surrounding environment.

Li, Yue; Duan, Yan-Ping, E-mail: duanyanping@tongji.edu.cn; Huang, Fan; Yang, Jing; Xiang, Nan; Meng, Xiang-Zhou; Chen, Ling

2014-06-01T23:59:59.000Z

370

Effects of oxygenate concentration on species mole fractions in premixed n-heptane flames  

E-Print Network [OSTI]

-heptane/oxygenate mixtures were 2.7 and 3.4. Three different fuel oxygenates (i.e. MTBE, methanol, and ethanol) were tested tertiary-butyl ether (MTBE), ethyl tertiary-butyl ether (ETBE), and tertiary amyl methyl ether (TAME)) were considered as possible fuel oxygenates. MTBE and ethanol are the most common oxygenates currently used

Senkan, Selim M.

371

Methylated trivalent arsenicals are potent inhibitors of glucose stimulated insulin secretion by murine pancreatic islets  

SciTech Connect (OSTI)

Epidemiologic evidence has linked chronic exposure to inorganic arsenic (iAs) with an increased prevalence of diabetes mellitus. Laboratory studies have identified several mechanisms by which iAs can impair glucose homeostasis. We have previously shown that micromolar concentrations of arsenite (iAs{sup III}) or its methylated trivalent metabolites, methylarsonite (MAs{sup III}) and dimethylarsinite (DMAs{sup III}), inhibit the insulin-activated signal transduction pathway, resulting in insulin resistance in adipocytes. Our present study examined effects of the trivalent arsenicals on insulin secretion by intact pancreatic islets isolated from C57BL/6 mice. We found that 48-hour exposures to low subtoxic concentrations of iAs{sup III}, MAs{sup III} or DMAs{sup III} inhibited glucose-stimulated insulin secretion (GSIS), but not basal insulin secretion. MAs{sup III} and DMAs{sup III} were more potent than iAs{sup III} as GSIS inhibitors with estimated IC{sub 50} ? 0.1 ?M. The exposures had little or no effects on insulin content of the islets or on insulin expression, suggesting that trivalent arsenicals interfere with mechanisms regulating packaging of the insulin transport vesicles or with translocation of these vesicles to the plasma membrane. Notably, the inhibition of GSIS by iAs{sup III}, MAs{sup III} or DMAs{sup III} could be reversed by a 24-hour incubation of the islets in arsenic-free medium. These results suggest that the insulin producing pancreatic ?-cells are among the targets for iAs exposure and that the inhibition of GSIS by low concentrations of the methylated metabolites of iAs may be the key mechanism of iAs-induced diabetes. - Highlights: ? Trivalent arsenicals inhibit glucose stimulated insulin secretion by pancreatic islets. ? MAs{sup III} and DMAs{sup III} are more potent inhibitors than arsenite with IC{sub 50} ? 0.1 ?M. ? The arsenicals have little or no effects on insulin expression in pancreatic islets. ? The inhibition of insulin secretion by arsenite, MAs{sup III} or DMAs{sup III} is reversible. ? Thus, pancreatic ?-cells may be primary targets for chronic exposure to arsenic.

Douillet, Christelle [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Currier, Jenna [Curriculum in Toxicology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Saunders, Jesse [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States); Bodnar, Wanda M. [Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431 (United States); Matoušek, Tomáš [Institute of Analytical Chemistry of the ASCR, v.v.i., Veve?í 97, 602 00 Brno (Czech Republic); Stýblo, Miroslav, E-mail: styblo@med.unc.edu [Department of Nutrition, Gillings School of Global Public Health, 2302 MHRC, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461 (United States)

2013-02-15T23:59:59.000Z

372

Synthesis and properties of poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid)/PbS hybrid composite  

SciTech Connect (OSTI)

The synthesis of a new hybrid composite based on PbS nanoparticles and poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid) [P(MMA-AMPSA)] copolymer is reported. The chemical synthesis consists in two steps: (i) a surfactant-free emulsion copolymerization between methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid and (ii) the generation of PbS particles in the presence of the P(MMA-AMPSA) latex, from the reaction between lead nitrate and thiourea. The composite was studied by scanning electron microscopy (SEM), X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The microstructure observed using SEM proves that the PbS nanoparticles are well dispersed in the copolymer matrix. The X-ray diffraction measurements demonstrate that the PbS nanoparticles have a cubic rock salt structure. It was also found that the inorganic semiconductor nanoparticles improve the thermal stability of the copolymer matrix.

Preda, N., E-mail: nicol@infim.ro [National Institute of Materials Physics, Multifunctional Materials and Structures Laboratory, P.O. Box MG-7, 77125 Bucharest (Romania); Rusen, E. [University Politehnica Bucharest, Department of Polymer Science, Calea Victoriei No. 71101, Bucharest (Romania)] [University Politehnica Bucharest, Department of Polymer Science, Calea Victoriei No. 71101, Bucharest (Romania); Musuc, A. [Institute of Physical Chemistry, 060021 Bucharest (Romania)] [Institute of Physical Chemistry, 060021 Bucharest (Romania); Enculescu, M.; Matei, E. [National Institute of Materials Physics, Multifunctional Materials and Structures Laboratory, P.O. Box MG-7, 77125 Bucharest (Romania)] [National Institute of Materials Physics, Multifunctional Materials and Structures Laboratory, P.O. Box MG-7, 77125 Bucharest (Romania); Marculescu, B. [University Politehnica Bucharest, Department of Polymer Science, Calea Victoriei No. 71101, Bucharest (Romania)] [University Politehnica Bucharest, Department of Polymer Science, Calea Victoriei No. 71101, Bucharest (Romania); Fruth, V. [Institute of Physical Chemistry, 060021 Bucharest (Romania)] [Institute of Physical Chemistry, 060021 Bucharest (Romania); Enculescu, I. [National Institute of Materials Physics, Multifunctional Materials and Structures Laboratory, P.O. Box MG-7, 77125 Bucharest (Romania)] [National Institute of Materials Physics, Multifunctional Materials and Structures Laboratory, P.O. Box MG-7, 77125 Bucharest (Romania)

2010-08-15T23:59:59.000Z

373

Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models  

SciTech Connect (OSTI)

Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-? (TNF-?) and interleukin-6 (IL-6). MP and EP decreased NF-?B expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models. -- Highlights: ? Efficacy of MP and EP in combating inflammation was displayed in several models. ? MP and EP reduced carrageenan-induced rat paw edema and prostaglandin E2 level. ? MP and EP decreased TNF-? and IL-6 levels in experimental endotoxemia. ? MP and EP reduced NF-?B expression and histological changes in rat liver and lung. ? MP and EP reduced croton oil-induced ear edema and neutrophil infiltration.

Saeed, Noha M. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt)] [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt); El-Demerdash, Ebtehal [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)] [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt); Abdel-Rahman, Hanaa M. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt)] [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt); Algandaby, Mardi M. [Department of Biology (Botany), Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia)] [Department of Biology (Botany), Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Al-Abbasi, Fahad A. [Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia)] [Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Naim, Ashraf B., E-mail: abnaim@pharma.asu.edu.eg [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)

2012-10-01T23:59:59.000Z

374

Methyl viologen mediated oxidation-reduction across dihexadecylphosphate vesicles involves transmembrane diffusion  

SciTech Connect (OSTI)

Numerous reports have appeared describing oxidation-reduction across bilayer membranes. Mechanisms proposed for specific systems include the following: (i) electron tunneling across the hydrocarbon barrier between interfacially bound redox partners, (ii) molecular diffusion of bound redox components across the barrier, and (iii) formation of barrier-penetrating aggregates, or electron-conducting channels, across the bilayer. Nonetheless, the actual reaction mechanisms remain obscure due to the general unavailability of transverse diffusion rates, possible loss of compartmentation of reactants, particularly in photochemical systems, and the ambiguities inherent in deducing reaction mechanisms from rate data, which form the primary evidence in most systems studied. The reactions of dihexadecylphosphate (DHP) vesicle-bound methyl viologen (MV/sup 2 +/) describes in this report are unique in allowing deduction of molecular details of a transmembrane redox event from the product composition and microphase distribution. Specifically, they have found that MV/sup 2 +/ bound at the outer vesicle interface mediates reduction of inner-localized MV/sup 2 +/ by dithionite ion in bulk solution in a manner that requires comigration of MV/sup +/ with the electron transferred across the membrane barrier.

Patterson, B.C.; Thompson, D.H.; Hurst, J.K.

1988-05-25T23:59:59.000Z

375

Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Modules: Preprint  

SciTech Connect (OSTI)

Concentrating photovoltaic (CPV) technology has recently gained interest based on their expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems use Fresnel lenses made of poly(methyl methacrylate)(PMMA) to obtain a high optical flux density. The optical and mechanical durability of such components, however, are not well established relative to the desired service life of 30 years. Specific reliability issues may include: reduced optical transmittance, discoloration, hazing, surface erosion, embrittlement, crack growth, physical aging, shape setting (warpage), and soiling. The initial results for contemporary lens- and material-specimens aged cumulatively to 6 months are presented. The study here uses an environmental chamber equipped with a xenon-arc lamp to age specimens at least 8x the nominal field rate. A broad range in the affected characteristics (including optical transmittance, yellowness index, mass loss, and contact angle) has been observed to date, depending on the formulation of PMMA used. The most affected specimens are further examined in terms of their visual appearance, surface roughness (examined via atomic force microscopy), and molecular structure (via Fourier transform infrared spectroscopy).

Miller, D. C.; Gedvilas, L. M.; To, B.; Kennedy, C. E.; Kurtz, S. R.

2010-08-01T23:59:59.000Z

376

Association between body mass index and arsenic methylation efficiency in adult women from southwest U.S. and northwest Mexico  

SciTech Connect (OSTI)

Human arsenic methylation efficiency has been consistently associated with arsenic-induced disease risk. Interindividual variation in arsenic methylation profiles is commonly observed in exposed populations, and great effort has been put into the study of potential determinants of this variability. Among the factors that have been evaluated, body mass index (BMI) has not been consistently associated with arsenic methylation efficiency; however, an underrepresentation of the upper BMI distribution was commonly observed in these studies. This study investigated potential factors contributing to variations in the metabolism of arsenic, with specific interest in the effect of BMI where more than half of the population was overweight or obese. We studied 624 adult women exposed to arsenic in drinking water from three independent populations. Multivariate regression models showed that higher BMI, arsenic (+ 3 oxidation state) methyltransferase (AS3MT) genetic variant 7388, and higher total urinary arsenic were significantly associated with low percentage of urinary arsenic excreted as monomethylarsonic acid (%uMMA) or high ratio between urinary dimethylarsinic acid and uMMA (uDMA/uMMA), while AS3MT genetic variant M287T was associated with high %uMMA and low uDMA/uMMA. The association between BMI and arsenic methylation efficiency was also evident in each of the three populations when studied separately. This strong association observed between high BMI and low %uMMA and high uDMA/uMMA underscores the importance of BMI as a potential arsenic-associated disease risk factor, and should be carefully considered in future studies associating human arsenic metabolism and toxicity.

Gomez-Rubio, Paulina [Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ (United States); Roberge, Jason; Arendell, Leslie; Harris, Robin B.; O'Rourke, Mary K.; Chen, Zhao [Division of Epidemiology and Biostatistics, College of Public Health, University of Arizona, Tucson, AZ (United States); Cantu-Soto, Ernesto; Meza-Montenegro, Maria M. [Department of Environmental Sciences, Instituto Tecnologico de Sonora, Ciudad Obregon, Sonora (Mexico); Billheimer, Dean [Department of Agricultural and Biosystems Engineering, University of Arizona, Tucson, AZ (United States); Lu Zhenqiang [Arizona Statistical Consulting Laboratory, University of Arizona, Tucson, AZ (United States); Klimecki, Walter T., E-mail: klimecki@pharmacy.arizona.edu [Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ (United States)

2011-04-15T23:59:59.000Z

377

Hydrogenolysis of methyl formate over copper on silica. I. Study of surface species by in situ infrared spectroscopy  

SciTech Connect (OSTI)

The hydrogenolysis of methyl formate to methanol over silica-supported copper has been studied using in situ infrared spectroscopy coupled with simultaneous determination of rate. Under flow reaction conditions two forms of adsorbed methyl formate exist. One has a carbonyl absorption at 1726 cm/sup -1/ and is bound to the support by the hydrogen bonding with a heat of adsorption of 65 kJ mol/sup -1/. The second absorbs at 1666 cm/sup -1/ and is bound to copper with an approximate heat of adsorption of 140 kJ mol/sup -1/. At 457 K the hydrogenolysis rate is directly proportional to the band intensity of the latter and hence it, or another species in equilibrium with it, is involved in the rate-determining step. Adsorption of CO from CO/H/sub 2/ mixtures gives rise to a single infrared band at 2117 cm/sup -1/, the corresponding heat of adsorption being 60 kJ mol/sup -1/. Competitive measurements under hydrogenolysis conditions show that methyl formate will partially displace adsorbed CO and not vice versa. Nonetheless CO does reversibly inhibit the rate and this is attributed to its adsorption displacing hydrogen from the surface. The lower concentration of surface hydrogen also reduces the rate of hydrogenation of a formaldehyde intermediate leading to its deposition as a polymer as revealed by infrared bands at 1483 and 1375 cm/sup -1/. The same polymer accretes more rapidly during the reverse methanol to methyl formate reaction for which CO is a substantial by-product and hydrogen pressures are much lower than used for hydrogenolysis. Continuous deactivation of the catalyst is then observed.

Monti, D.M.; Cant, N.W.; Trimm, D.L.; Wainwright, M.S.

1986-07-01T23:59:59.000Z

378

Z .The Science of the Total Environment 261 2000 91 98 Mercury methylation along a lake forest transect in  

E-Print Network [OSTI]

and acidified controls 1 3 g dry wt. were slurried with local water and incubated in the dark at 25 28 C for y1 those heavily Z . Z y2 .colonized with periphyton 3.4 5.4% . Methylation in surface or near-bottom water: jeanrdg@biof.ufrj.br J.R. Guimaraes .~ 0048-9697r00r$ - see front matter 2000 Elsevier Science B.V. All

Long, Bernard

379

Evaluating the Identity and Diiron Core Transformations of a (?-Oxo)diiron(III) Complex Supported by Electron-Rich Tris(pyridyl-2-methyl)amine Ligands  

E-Print Network [OSTI]

The composition of a (?-oxo)diiron(III) complex coordinated by tris[(3,5-dimethyl-4-methoxy)pyridyl-2-methyl]amine (R[subscript 3]TPA) ligands was investigated. Characterization using a variety of spectroscopic methods and ...

Do, Loi H.

380

Oxidation Kinetics of Pure and Blended Methyl Octanoate/n-Nonane/Methylcyclohexane: Measurements and Modeling of OH*/CH* Chemiluminescence, Ignition Delay Times and Laminar Flame Speeds  

E-Print Network [OSTI]

fuels at 1.5 atm indicated the following ignition delay time order, from shortest to longest: methyl octanoate atm (nominal) the order remained, in general, consistent. Under fuel-lean conditions, ignition...

Rotavera, Brandon Michael

2012-07-16T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Structural and biochemical insights into 2?-O-methylation at the 3?-terminal nucleotide of RNA by Hen1  

SciTech Connect (OSTI)

Small RNAs of {approx}20-30 nt have diverse and important biological roles in eukaryotic organisms. After being generated by Dicer or Piwi proteins, all small RNAs in plants and a subset of small RNAs in animals are further modified at their 3'-terminal nucleotides via 2'-O-methylation, carried out by the S-adenosylmethionine-dependent methyltransferase (MTase) Hen1. Methylation at the 3' terminus is vital for biological functions of these small RNAs. Here, we report four crystal structures of the MTase domain of a bacterial homolog of Hen1 from Clostridium thermocellum and Anabaena variabilis, which are enzymatically indistinguishable from the eukaryotic Hen1 in their ability to methylate small single-stranded RNAs. The structures reveal that, in addition to the core fold of the MTase domain shared by other RNA and DNA MTases, the MTase domain of Hen1 possesses a motif and a domain that are highly conserved and are unique to Hen1. The unique motif and domain are likely to be involved in RNA substrate recognition and catalysis. The structures allowed us to construct a docking model of an RNA substrate bound to the MTase domain of bacterial Hen1, which is likely similar to that of the eukaryotic counterpart. The model, supported by mutational studies, provides insight into RNA substrate specificity and catalytic mechanism of Hen1.

Chan, Chio Mui; Zhou, Chun; Brunzelle, Joseph S.; Huang, Raven H.; (UIUC); (NWU)

2010-01-28T23:59:59.000Z

382

Unexpected effects of gene deletion on mercury interactions with the methylation-deficient mutant hgcAB  

SciTech Connect (OSTI)

The hgcA and hgcB gene pair is essential for mercury (Hg) methylation by certain anaerobic bacteria,1 but little is known about how deletion of hgcAB affects cell surface interactions and intracellular uptake of Hg. Here, we compare hgcAB mutants with the wild-type (WT) strains of both Geobacter sulfurreducens PCA and Desulfovibrio desulfuricans ND132 and observe differences in Hg redox transformations, adsorption, and uptake in laboratory incubation studies. In both strains, deletion of hgcAB increased the reduction of Hg(II) but decreased the oxidation of Hg(0) under anaerobic conditions. The measured cellular thiol content in hgcAB mutants was lower than the WT, accounting for decreased adsorption and uptake of Hg. Despite the lack of methylation activity, Hg uptake by the hgcAB continued, albeit at a slower rate than the WT. These findings demonstrate that deletion of the hgcAB gene not only eliminates Hg methylation but also alters cell physiology, resulting in changes to Hg redox reactions, sorption, and uptake by cells.

Lin, Hui [ORNL] [ORNL; Hurt, Jr., Richard Ashley [ORNL; Johs, Alexander [ORNL] [ORNL; Parks, Jerry M [ORNL] [ORNL; Morrell-Falvey, Jennifer L [ORNL] [ORNL; Liang, Liyuan [ORNL] [ORNL; Elias, Dwayne A [ORNL] [ORNL; Gu, Baohua [ORNL] [ORNL

2014-01-01T23:59:59.000Z

383

Nonpremixed ignition, laminar flame propagation, and mechanism reduction of n-butanol, iso-butanol, and methyl butanoate  

SciTech Connect (OSTI)

The non-premixed ignition temperature of n-butanol (CH{sub 3}CH{sub 2}CH{sub 2}CH{sub 2}OH), iso-butanol ((CH{sub 3}){sub 2}CHCH{sub 2}OH) and methyl butanoate (CH{sub 3}CH{sub 2}CH{sub 2}COOCH{sub 3}) was measured in a liquid pool assembly by heated oxidizer in a stagnation flow for system pressures of 1 and 3 atm. In addition, the stretch-corrected laminar flame speeds of mixtures of air–n-butanol/iso-butanol/methyl butanoate were determined from the outwardly propagating spherical flame at initial pressures of up to 2 atm, for an extensive range of equivalence ratio. The ignition temperature and laminar flame speeds of n-butanol and methyl butanoate were computationally simulated with three recently developed kinetic mechanisms in the literature. Dominant reaction pathways to ignition and flame propagation were identified and discussed through a chemical explosive mode analysis (CEMA) and sensitivity analysis. The detailed models were further reduced through a series of systematic strategies. The reduced mechanisms provided excellent agreement in both homogeneous and diffusive combustion environments and greatly improved the computation efficiency.

Lu, Wei; Kelley, A. P.; Law, C. K.

2011-01-01T23:59:59.000Z

384

Published Ahead of Print 1 July 2011. 2011, 193(17):4549. DOI: 10.1128/JB.00415-11.J. Bacteriol.  

E-Print Network [OSTI]

Laboratory, Joint Genome Institute, Biosciences Division Genome Science B6, Los Alamos, New Mexico 875454 ; U and energy source (9, 10, 11, 14). This strain can also grow on other ethers (e.g., 2-methyl-1,3- dioxolane and butyl methyl ether), alcohols, and benzene as the sole carbon and energy source, and it can grow

Alvarez-Cohen, Lisa

385

UNIVERSITY OF CALIFORNIA Santa Barbara  

E-Print Network [OSTI]

, B. Dooher, and D. Rice, Analysis of dissolved benzene plumes and methyl tertiary butyl ether (MTBE, An evaluation of MTBE impacts to California groundwater resources, pp. 68 p., Lawrence Livermore National, Temporal Analysis of Methyl Tertiary Butyl Ether (MTBE) Plumes at California Leaking Underground Fuel tank

California at Santa Barbara, University of

386

Vapor-liquid equilibrium data at 298. 15 K for binary systems containing methyl acetate or methanol with 2-methoxyethanol or 2-ethoxyethanol  

SciTech Connect (OSTI)

Isothermal vapor-liquid equilibria were measured at 298.15 K for the systems containing methyl acetate or methanol with 2-methoxyethanol or 2-ethoxyethanol. Mixtures containing methanol show a behavior close to ideal, while those containing methyl acetate exhibit positive deviations from ideality and satisfy the Redlich-Kister thermodynamic consistency test. The liquid-phase activity coefficients were fitted by using the van Laar, Wilson, NRTL, and NRTL-m (a modified NRTL equation) equations.

Martin, M.C.; Cocero, M.J.; Mato, F.B. (Univ. de Valladolid (Spain))

1994-07-01T23:59:59.000Z

387

13-03-09 9:37 PMModernity, the Cold War, and New Whig Histories of Ideas, Pt. 2 | Ether Wave Propaganda Page 1 of 4http://etherwave.wordpress.com/2012/10/21/modernity-the-cold-war-and-new-whig-histories-of-ideas-pt-2/  

E-Print Network [OSTI]

13-03-09 9:37 PMModernity, the Cold War, and New Whig Histories of Ideas, Pt. 2 | Ether Wave Propaganda Page 1 of 4http://etherwave.wordpress.com/2012/10/21/modernity-the-cold-war-and-new-whig-histories-of-ideas-pt-2/ Modernity, the Cold War, and New Whig Histories of Ideas, Pt. 2 October 21, 2012 Posted

Solovey, Mark

388

12-11-24 7:47 PMModernity, the Cold War, and New Whig Histories of Ideas, Pt. 3 Ether Wave Propaganda Page 1 of 6http://etherwave.wordpress.com/2012/11/17/modernity-the-cold-war-and-new-whig-histories-of-ideas-pt-3/  

E-Print Network [OSTI]

12-11-24 7:47 PMModernity, the Cold War, and New Whig Histories of Ideas, Pt. 3 « Ether Wave Propaganda Page 1 of 6http://etherwave.wordpress.com/2012/11/17/modernity-the-cold-war-and-new-whig-histories-of-ideas-pt-3/ Modernity, the Cold War, and New Whig Histories of Ideas, Pt. 3 November 17, 2012 Posted

Solovey, Mark

389

13-03-09 9:32 PMModernity, the Cold War, and New Whig Histories of Ideas, Pt. 1 | Ether Wave Propaganda Page 1 of 6http://etherwave.wordpress.com/2012/09/22/modernity-the-cold-war-and-new-whig-histories-of-ideas-pt-1/  

E-Print Network [OSTI]

13-03-09 9:32 PMModernity, the Cold War, and New Whig Histories of Ideas, Pt. 1 | Ether Wave Propaganda Page 1 of 6http://etherwave.wordpress.com/2012/09/22/modernity-the-cold-war-and-new-whig-histories-of-ideas-pt-1/ Modernity, the Cold War, and New Whig Histories of Ideas, Pt. 1 September 22, 2012 Posted

Solovey, Mark

390

Emissions and engine performance from blends of soya and canola methyl esters with ARB {number_sign}2 diesel in a DCC 6V92TA MUI engine  

SciTech Connect (OSTI)

A Detroit Diesel 6V92TA MUI engine was operated on several blends of EPA No. 2 diesel, California ARB No. 2 diesel, soya methyl ester (SME) and canola methyl ester (CME). Various fuels and fuel blend characteristics were determined and engine emissions from these fuels and blends were compared. Increasing percentages of SME and CME blended with either ARB or EPA diesels led to increased emissions of NO{sub x}, CO{sub 2} and soluble particulate matter. Also noted were reductions in total hydrocarbons, CO and insoluble particulate matter. Chassis dynamometer tests conducted on a 20/80 SME/ARB blend showed similar emissions trends. The data suggest that certain methyl ester/No. 2 diesel blends in conjunction with delays in engine timing and technologies that reduce the soluble fraction of particulate emissions merit further exploration as emissions reducing fuel options for North American mass transits (except in California, which mandates ARB diesel).

Spataru, A.; Romig, C.

1995-12-31T23:59:59.000Z

391

Emissions and engine performance from blends of soya and canola methyl esters with ARB No. 2 diesel in a DDC 6V92TA MUI engine  

SciTech Connect (OSTI)

A Detroit Diesel 6V92TA MUI engine was operated on several blends of EPA No. 2 diesel, soya methyl ester (SME) and canola methyl ester (CME). Various fuels and fuel blend characteristics were determined and engine emissions from these fuels and blends were compared. Increasing percentages of SME and CME blended with either ARB or EPA diesels led to increased emissions of NO{sub x}, CO{sub 2} and soluble particulate matter. Also noted were reductions in total hydrocarbons, CO and insoluble particulate matter. Chassis dynamometer tests conducted on a 20/80 SME/ARB blend showed similar emission trends. The data suggest that certain methyl ester/No. 2 diesel blends in conjunction with technologies that reduce the soluble fraction of particulate emissions merit further exploration as emissions reducing fuel options for North American mass transit sectors (except California, which mandates ARB diesel).

Spataru, A.; Romig, C. [ADEPT Group, Inc., Los Angeles, CA (United States)

1995-11-01T23:59:59.000Z

392

13-03-09 9:30 PMCold War Social Science and the Rubric of the "Cold War" | Ether Wave Propaganda Page 1 of 6http://etherwave.wordpress.com/2012/09/06/cold-war-social-science-and-the-rubric-of-the-cold-war/  

E-Print Network [OSTI]

13-03-09 9:30 PMCold War Social Science and the Rubric of the "Cold War" | Ether Wave Propaganda Page 1 of 6http://etherwave.wordpress.com/2012/09/06/cold-war-social-science-and-the-rubric-of-the-cold-war/ Cold War Social Science and the Rubric of the "Cold War" September 6, 2012 Posted by Will Thomas in EWP

Solovey, Mark

393

Alkylating agent methyl methanesulfonate (MMS) induces a wave of global protein hyperacetylation: Implications in cancer cell death  

SciTech Connect (OSTI)

Protein acetylation modification has been implicated in many cellular processes but the direct evidence for the involvement of protein acetylation in signal transduction is very limited. In the present study, we found that an alkylating agent methyl methanesulfonate (MMS) induces a robust and reversible hyperacetylation of both cytoplasmic and nuclear proteins during the early phase of the cellular response to MMS. Notably, the acetylation level upon MMS treatment was strongly correlated with the susceptibility of cancer cells, and the enhancement of MMS-induced acetylation by histone deacetylase (HDAC) inhibitors was shown to increase the cellular susceptibility. These results suggest protein acetylation is important for the cell death signal transduction pathway and indicate that the use of HDAC inhibitors for the treatment of cancer is relevant.

Lee, Min-Young [Department of Biochemistry, College of Medicine, Dong-A University, 3-1, Dongdaeshin-Dong, Seo-Gu, Busan 602-714, South Korea (Korea, Republic of); Kim, Myoung-Ae [Department of Biochemistry, College of Medicine, Dong-A University, 3-1, Dongdaeshin-Dong, Seo-Gu, Busan 602-714, South Korea (Korea, Republic of); Kim, Hyun-Ju [Department of Biochemistry, College of Medicine, Dong-A University, 3-1, Dongdaeshin-Dong, Seo-Gu, Busan 602-714, South Korea (Korea, Republic of); Bae, Yoe-Sik [Department of Biochemistry, College of Medicine, Dong-A University, 3-1, Dongdaeshin-Dong, Seo-Gu, Busan 602-714, South Korea (Korea, Republic of); Park, Joo-In [Department of Biochemistry, College of Medicine, Dong-A University, 3-1, Dongdaeshin-Dong, Seo-Gu, Busan 602-714, South Korea (Korea, Republic of); Kwak, Jong-Young [Department of Biochemistry, College of Medicine, Dong-A University, 3-1, Dongdaeshin-Dong, Seo-Gu, Busan 602-714, South Korea (Korea, Republic of); Chung, Jay H. [Laboratory of Biochemical Genetics, NHLBI, NIH, 10 Center Drive, Bethesda, MD 20892 (United States); Yun, Jeanho [Department of Biochemistry, College of Medicine, Dong-A University, 3-1, Dongdaeshin-Dong, Seo-Gu, Busan 602-714, South Korea (Korea, Republic of)]. E-mail: yunj@dau.ac.kr

2007-08-24T23:59:59.000Z

394

(E)-2-[(2-Bromophenylimino)methyl]-5-methoxyphenol: X-ray and DFT-calculated structures  

SciTech Connect (OSTI)

The crystal structure of (E)-2-[(2-Bromophenylimino)methyl]-5-methoxyphenol is determined by using X-ray diffraction and then the molecular structure is investigated with density functional theory (DFT). X-Ray study shows that the title compound has a strong intramolecular O-H-N hydrogen bond and three dimensional crystal structure is primarily determined by C-H-{pi} and weak van der Waals interactions. The strong O-H-N bond is an evidence of the preference for the phenol-imine tautomeric form in the solid state. Optimized molecular geometry is calculated with DFT at the B3LYP/6-31G(d,p) level. The IR spectra of compound were recorded experimentally and calculated to compare with each other. The results from both experiment and theoretical calculations are compared in this study.

Kosar, B., E-mail: bkosar@omu.edu.tr; Albayrak, C. [Sinop University, Faculty of Education (Turkey); Odabasoglu, M. [Pamukkale University, Chemistry Program (Turkey); Bueyuekguengoer, O. [Ondokuz Mayis University, Faculty of Arts and Sciences (Turkey)

2010-12-15T23:59:59.000Z

395

Evidence for Thiol-Dependent Production of Oxygen Radicals by 4-Methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione  

E-Print Network [OSTI]

to a peroxide species that undergoes a trace metal-catalyzed, Fenton-type reaction to generate oxygen radicalsEvidence for Thiol-Dependent Production of Oxygen Radicals by 4-Methyl-5-pyrazinyl-3H-1,2-dithiole the conversion of molecular oxygen to reactive oxygen radicals. Using a plasmid-based assay that monitors DNA

Gates, Kent. S.

396

Electronic Structures and Spin Topologies of -Picoliniumyl Radicals. A Study of the Homolysis of N-Methyl--picolinium and of Benzo-, Dibenzo-, and Naphthoannulated  

E-Print Network [OSTI]

topologies in metalloenzymes. Introduction The redox reactions of quaternized nitrogen heterocycles interesting. For example, the herbicide methyl viologen (paraquat) and the promising antitumor agent equivalent of superoxide O2 ·-.1­4 The repeated enzymatic reduction and back-oxidation by O2, i.e., the redox

Glaser, Rainer

397

Standard Thermodynamic Functions of Tripeptides N-Formyl-L-Methionyl-L-Leucyl-L-Phenylalaninol and N-Formyl-L-Methionyl-L-Leucyl-L-Phenylalanine Methyl Ester  

E-Print Network [OSTI]

The heat capacities of tripeptides N-formyl-l-methionyl-l-leucyl-l-phenylalaninol (N-f-MLF-OH) and N-formyl-l-methionyl-l-leucyl-l-phenylalanine methyl ester (N-f-MLF-OMe) were measured by precision adiabatic vacuum ...

Markin, Alexey V.

398

Electron-electron and electron-phonon interactions in irradiated N-methyl pyridinium derivatives with TCNQ studied by optical spectroscopy  

E-Print Network [OSTI]

1417 Electron-electron and electron-phonon interactions in irradiated N-methyl pyridinium derivatives with TCNQ studied by optical spectroscopy A. Graja and R. Swietlik Institute of Molecular Physics le 13 mars 1985, accepti le ler avril 1985) Résumé. 2014 L'irradiation électronique des

Boyer, Edmond

399

TpPtMe(H)2: Why Is There H/D Scrambling of the Methyl Group but Not Methane Loss?  

E-Print Network [OSTI]

TpPtMe(H)2: Why Is There H/D Scrambling of the Methyl Group but Not Methane Loss? Mark A. Iron, H ) hydrido-tris(pyrazolyl)borate) was investigated. This complex is remarkably resistant to methane loss; heating it in methanol at 55 °C does not lead to either methane or hydrogen loss. When CD3OD is used

Keinan, Ehud

400

Composition and method for encapsulating photovoltaic devices  

DOE Patents [OSTI]

A composition and method for encapsulating a photovoltaic device which minimizes discoloration of the encapsulant. The composition includes an ethylene-vinyl acetate encapsulant, a curing agent, an optional ultraviolet light stabilizer, and/or an optional antioxidant. The curing agent is preferably 1,1-di-(t-butylperoxy)-3,3,5-trimethylcyclohexane; the ultraviolet light stabilizer is bis-(N-octyloxy-tetramethyl) piperidinyl sebacate and the antioxidant is selected from the group consisting of tris (2,4-di-tert-butylphenyl) phosphite, tetrakis methylene (3,5-di-tert-butyl-4-hydroxyhydrocinnamate) methane, octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate, and 2,2'-ethylidene bis(4,6-di-t-butylphenyl) fluorophosponite. The composition is applied to a solar cell then cured. The cured product contains a minimal concentration of curing-generated chromophores and resists UV-induced degradation.

Pern, Fu-Jann (Golden, CO)

2000-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

High Temperature, Low Relative Humidity, Polymer-type Membranes Based on Disulfonated Poly(arylene ether) Block and Random Copolymers Optionally Incorporating Protonic Conducting Layered Water insoluble Zirconium Fillers  

SciTech Connect (OSTI)

Our research group has been engaged in the past few years in the synthesis of biphenol based partially disulfonated poly(arylene ether sulfone) random copolymers as potential PEMs. This series of polymers are named as BPSH-xx, where BP stands for biphenol, S stands for sulfonated, H stands for acidified and xx represents the degree of disulfonation. All of these sulfonated copolymers phase separate to form nano scale hydrophilic and hydrophobic morphological domains. The hydrophilic phase containing the sulfonic acid moieties causes the copolymer to absorb water. Water confined in hydrophilic pores in concert with the sulfonic acid groups serve the critical function of proton (ion) conduction and water transport in these systems. Both Nafion and BPSH show high proton conductivity at fully hydrated conditions. However proton transport is especially limited at low hydration level for the BPSH random copolymer. It has been observed that the diffusion coefficients of both water and protons change with the water content of the pore. This change in proton and water transport mechanisms with hydration level has been attributed to the solvation of the acid groups and the amount of bound and bulk-like water within a pore. At low hydration levels most of the water is tightly associated with sulfonic groups and has a low diffusion coefficient. This tends to encourage isolated domain morphology. Thus, although there may be significant concentrations of protons, the transport is limited by the discontinuous morphological structure. Hence the challenge lies in how to modify the chemistry of the polymers to obtain significant protonic conductivity at low hydration levels. This may be possible if one can alter the chemical structure to synthesize nanophase separated ion containing block copolymers. Unlike the BPSH copolymers, where the sulfonic acid groups are randomly distributed along the chain, the multiblock copolymers will feature an ordered sequence of hydrophilic and hydrophobic segments. If, like in Nafion, connectivity is established between the hydrophilic domains in these multiblock copolymers, they will not need as much water, and hence will show much better protonic conductivity than the random copolymers (with similar degree of sulfonation, or IEC) at partially hydrated conditions. The goal of this research is to develop a material suitable for use as a polymer electrolyte membrane which by the year 2010 will meet all the performance requirements associated with fuel cell operation at high temperatures and low relative humidity, and will out-perform the present standard Nafion{reg_sign}. In particular, it is our objective to extend our previous research based on the use of thermally, oxidatively, and hydrolytically, ductile, high Tg ion containing polymers based on poly(arylene ethers) to the production of polymer electrolyte membranes which will meet all the performance requirements in addition to having an areal resistance of < 0.05 ohm-cm{sup 2} at a temperature of up to 120 C, relative humidity of 25 to 50%, and up to 2.5 atm total pressure. In many instances, our materials already out performs Nafion{reg_sign}, and it is expected that with some modification by either combining with conductive inorganic fillers and/or synthesizing as a block copolymer it will meet the performance criteria at high temperatures and low relative humidity. A key component in improving the performance of the membranes (and in particular proton conductivity) and meeting the cost requirements of $40/m{sup 2} is our development of a film casting process, which shows promise for generation of void free thin films of uniform thickness with controlled polymer alignment and configuration.

McGrath, James E.; Baird, Donald G.

2010-06-03T23:59:59.000Z

402

Gestational exposure to diethylstilbestrol alters cardiac structure/function, protein expression and DNA methylation in adult male mice progeny  

SciTech Connect (OSTI)

Pregnant women, and thus their fetuses, are exposed to many endocrine disruptor compounds (EDCs). Fetal cardiomyocytes express sex hormone receptors making them potentially susceptible to re-programming by estrogenizing EDCs. Diethylstilbestrol (DES) is a proto-typical, non-steroidal estrogen. We hypothesized that changes in adult cardiac structure/function after gestational exposure to the test compound DES would be a proof in principle for the possibility of estrogenizing environmental EDCs to also alter the fetal heart. Vehicle (peanut oil) or DES (0.1, 1.0 and 10.0 ?g/kg/da.) was orally delivered to pregnant C57bl/6n dams on gestation days 11.5–14.5. At 3 months, male progeny were left sedentary or were swim trained for 4 weeks. Echocardiography of isoflurane anesthetized mice revealed similar cardiac structure/function in all sedentary mice, but evidence of systolic dysfunction and increased diastolic relaxation after swim training at higher DES doses. The calcium homeostasis proteins, SERCA2a, phospholamban, phospho-serine 16 phospholamban and calsequestrin 2, are important for cardiac contraction and relaxation. Immunoblot analyses of ventricle homogenates showed increased expression of SERCA2a and calsequestrin 2 in DES mice and greater molecular remodeling of these proteins and phospho-serine 16 phospholamban in swim trained DES mice. DES increased cardiac DNA methyltransferase 3a expression and DNA methylation in the CpG island within the calsequestrin 2 promoter in heart. Thus, gestational DES epigenetically altered ventricular DNA, altered cardiac function and expression, and reduced the ability of adult progeny to cardiac remodel when physically challenged. We conclude that gestational exposure to estrogenizing EDCs may impact cardiac structure/function in adult males. -- Highlights: ? Gestational DES changes cardiac SERCA2a and CASQ2 expression. ? Echocardiography identified systolic dysfunction and increased diastolic relaxation. ? DES increased DNMT3a expression and increased CpG DNA methylation. ? DES impacts fetal heart reducing cardiac reserve on challenge in adulthood. ? Fetal heart can be re-programmed by a non-steroidal estrogen.

Haddad, Rami, E-mail: rami.haddad@mail.mcgill.ca [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montréal, Québec, Canada H3T 1E2 (Canada) [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montréal, Québec, Canada H3T 1E2 (Canada); Division of Experimental Medicine, Department of Medicine, McGill University, 850 Sherbrooke Street, Montréal, Québec, Canada H3A 1A2 (Canada); Kasneci, Amanda, E-mail: amanda.kasneci@mail.mcgill.ca [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montréal, Québec, Canada H3T 1E2 (Canada)] [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montréal, Québec, Canada H3T 1E2 (Canada); Mepham, Kathryn, E-mail: katherine.mepham@mail.mcgill.ca [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montréal, Québec, Canada H3T 1E2 (Canada) [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montréal, Québec, Canada H3T 1E2 (Canada); Division of Experimental Medicine, Department of Medicine, McGill University, 850 Sherbrooke Street, Montréal, Québec, Canada H3A 1A2 (Canada); Sebag, Igal A., E-mail: igal.sebag@mcgill.ca [Division of Cardiology, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montréal, Québec, Canada H3T 1E2 (Canada); and others

2013-01-01T23:59:59.000Z

403

Vapor-liquid equilibria of binary and ternary mixtures of cyclohexane, 3-methyl-2-butanone, and octane at 101.3 kPa  

SciTech Connect (OSTI)

Vapor-liquid equilibria were measured at 101.3 kPa for the three binary and one ternary mixtures of cyclohexane, 3-methyl-2-butanone, and octane. The isobaric T-x-y data were reported, including an azeotropic point for the binary mixture cyclohexane + 3-methyl-2-butanone. The virial equation of state truncated after the second coefficient was used to calculate the vapor-phase fugacity coefficients. The Tsonopoulos correlation equation was applied to determine the second virial coefficients. Various activity coefficient models of the Wilson, the NRTL, and the UNIQUAC equations were used to correlate the binary experimental vapor-liquid equilibrium results. Optimally-fitted binary parameters of the activity coefficient models were obtained and those parameters of the NRTL model were employed to predict the ternary vapor-liquid equilibria. Satisfactory results were presented for the correlation and prediction of the vapor-liquid equilibrium data on binary and ternary mixtures.

Chen, C.C.; Tang, M.; Chen, Y.P. [National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Chemical Engineering] [National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Chemical Engineering

1996-05-01T23:59:59.000Z

404

Solution medium control of the photoredox yield in the Ru(bpy)/sub 3//sup 2 +//methyl viologen/EDTA system  

SciTech Connect (OSTI)

The observed quantum yield of formation of the methyl viologen radical cation, phi(MV/sup +/-), upon 450-nm irradiation of the Ru(bpy)/sub 3//sup 2 +//methyl viologen dication/EDTA system at pH 11.0 is dependent on the concentrations of all three components. Under the conditions of the experiments, phi(MV/sup +/-)approx. =2eta/sub cr/ where eta/sub cr/ is the efficiency of release of redox products from the solvent cage. The maximum value of eta/sub cr/ is approx. =0.17 at high concentrations of all components where the photosensitizer, electron relay, and sacrificial electron donor exist as ion-paired aggregates within a single solvent-caged unit. 3 figures.

Mandal, K.; Hoffman, M.Z.

1984-01-19T23:59:59.000Z

405

Studies on the binding of 5-N-methylated quindoline derivative to human telomeric G-quadruplex  

SciTech Connect (OSTI)

Research highlights: {yields} Hydrophobic interaction provided an important driving force for the interaction between ligand and G-quadruplex. {yields} Constrained water molecules were released from surface of G-tetrad upon the formation of the complex. {yields} The end-stacking mode for quindoline derivative was validated through UV-vis, ITC, steady-state, and time-resolved fluorescence experiment. {yields} The binding of compound 1 to quadruplex was found to be a temperature-dependent and enthalpy-entropy compensation process. -- Abstract: Quindoline derivatives as telomeric quadruplex ligands have shown good biological activity for telomerase inhibition. In the present study, we used spectroscopic and calorimetric methods to investigate the interactions between a quindoline derivative (5-methyl-11-(2-morpholinoethylamino)-10-H-indolo-[3,2-b]quinolin-5-ium iodide, compound 1) and human telomeric G-quadruplex. The thermodynamic studies using isothermal titration calorimetry (ITC) indicated that their binding process was temperature-dependent and enthalpy-entropy co-driven. The significant negative heat capacity was obtained experimentally from the temperature dependence of enthalpy changes, which was consistent with that from theoretical calculation, and all suggesting significant hydrophobic contribution to the molecular recognition process. Based on the results from UV-vis, ITC, steady-state and time-resolved fluorescence, their binding mode was determined as two ligand molecules stacking on the quartets on both ends of the quadruplex. These results shed light on rational design and development of quindoline derivatives as G-quadruplex binding ligands.

Xu, Wei; Tan, Jia-Heng; Chen, Shuo-Bin; Hou, Jin-Qiang; Li, Ding [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China)] [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Huang, Zhi-Shu, E-mail: ceshzs@mail.sysu.edu.cn [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China)] [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Gu, Lian-Quan, E-mail: cesglq@mail.sysu.edu.cn [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China)] [School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China)

2011-03-18T23:59:59.000Z

406

Complete kinetic isotope effect description of transition states for acid-catalyzed hydrolyses of methyl. cap alpha. - and. beta. -glucopyranosides  

SciTech Connect (OSTI)

The following kinetic isotope effects (k/sub light//k/sub heavy/) have been measured by the isotopic quasi-racemate method for the hydrolyses of methyl ..cap alpha..- and ..beta..-glucopyranosides, respectively in 2.0 M HClO/sub 4/ at 80/sup 0/C (..cap alpha..-D 1.137 +/- 0.007, 1.089 +/- 0.006; ..beta..-D 1.073 +/- 0.003, 1.045 +/- 0.004; ..gamma..-D (C5) 0.987 +/- 0.002, 0.971 +/- 0.003; leaving group d/sub 3/ 1.006 +/- 0.001, 1.015 +/- 0.002; leaving group /sup 18/O 1.026 +/- 0.001, 1.024 +/ +/- 0.002; anomeric /sup 13/C 1.007 +/- 0.001, 1.011 +/- 0.002). In conjunction with studies of the effect of added solutes on the rates of hydrolysis of various aldopyranosyl derivatives, which indicate such reactions are truly unimolecular, and model ring /sup 18/O and ..beta..-deuterium effects, it is possible to locate the dihedral angles about the O5-C1 and C1-C2 bonds at the transition state using these data. If the dihedral angles so derived are used as constraints in calculations using N.L. Allinger's MM2 molecular mechanics program, transition-state structures are obtained. The geometry of these transition states stands in contradiction to the theory of stereoelectronic control.

Bennet, A.J.; Sinnott, M.L.

1986-11-12T23:59:59.000Z

407

Electrogenic and electroneutral pathways for methyl viologen-mediated transmembrane oxidation-reduction across dihexadecylphosphate vesicular membranes  

SciTech Connect (OSTI)

Two pathways for transmembrane reduction of dihexadecylphosphate (DHP) vesicle-entrapped Co(bpy)[sub 3][sup 3+] ion by photogenerated methyl viologen radical cation have been identified by quantitative evaluation of the reaction kinetics. One pathway involves electrogenic diffusion of MV[sup +] and the other electroneutral diffusion of MV[sup 0] across the bilayer. The pathways were clearly distinguished by the self-impeding character of the electrogenic reaction, which was progressively retarded as the membrane polarization increased, and by the net stoichiometry of viologen uptake accompanying transmembrane oxidation-reduction. The first-order rate constants for transmembrane diffusion of MV[sup +] and MV[sup 0] were estimated to be 2.7 x 10[sup [minus]2] s[sup [minus]1] and 1.1 x 10[sup 3] s[sup [minus]1], respectively, at 23[degree]C. The rate constant for MV[sup +] diffusion is identical to the value previously measured by [sup 14]C-isotopic labeling methods, and other kinetic parameters were consistent with thermodynamic data obtained from measurements of Donnan equilibria. 31 refs., 7 figs., 2 tabs.

Lymar, S.V. (Oregon Graduate Inst. of Science and Technology, Portland, OR (United States) Inst. of Catalysis, Novosibirsk (Russian Federation)); Hurst, J.K. (Oregon Graduate Inst. of Science and Technology, Portland, OR (United States))

1994-01-20T23:59:59.000Z

408

Photocatalytic degradation of methyl orange dye in water solutions in the presence of MWCNT/TiO{sub 2} composites  

SciTech Connect (OSTI)

Highlights: ? MWCNTs/TiO{sub 2} composites were obtained to degrade organic dyes in water. ? MWCNT/TiO{sub 2} composites were analyzed by photocatalysis and structural characterization. ? The photocatalytic shows efficient method for the degradation of dyes from aqueous effluents. - Abstract: The textile and dyestuff industries are the primary sources of the release of synthetic dyes into the environment and usually there are major pollutants in dye wastewaters. Because of their toxicity and slow degradation, these dyes are categorized as environmentally hazardous materials. In this context, carbon nanotubes/TiO{sub 2} (CNTs/TiO{sub 2}) composites were prepared using multi-walled CNTs (MWCNTs), titanium (IV) propoxide and commercial TiO{sub 2} (P25{sup ®}) as titanium oxide sources, to degrade the methyl orange dye in solution through photocatalyst activity using UV irradiation. The composites were prepared by solution processing followed by thermal treatment at 400, 500 and 600 °C. The heterojunction between nanotubes and TiO{sub 2} was confirmed by XRD, specific surface area. The coating morphology was observed with SEM and TEM.

Da Dalt, S., E-mail: silvana.da.dalt@ufrgs.br [Department of Material, Federal University of Rio Grande do Sul, Av. Osvaldo Aranha 99, Laboratory 705C, ZIP 90035-190, Porto Alegre, RS (Brazil); Alves, A.K.; Bergmann, C.P. [Department of Material, Federal University of Rio Grande do Sul, Av. Osvaldo Aranha 99, Laboratory 705C, ZIP 90035-190, Porto Alegre, RS (Brazil)

2013-05-15T23:59:59.000Z

409

Poly(methyl methacrylate) as a self-assembled gate dielectric for graphene field-effect transistors  

SciTech Connect (OSTI)

We investigate poly(methyl methacrylate) (PMMA) as a low thermal budget organic gate dielectric for graphene field effect-transistors (GFETs) based on a simple process flow. We show that high temperature baking steps above the glass transition temperature (?130?°C) can leave a self-assembled, thin PMMA film on graphene, where we get a gate dielectric almost for “free” without additional atomic layer deposition type steps. Electrical characterization of GFETs with PMMA as a gate dielectric yields a dielectric constant of k?=?3.0. GFETs with thinner PMMA dielectrics have a lower dielectric constant due to decreased polarization arising from neutralization of dipoles and charged carriers as baking temperatures increase. The leakage through PMMA gate dielectric increases with decreasing dielectric thickness and increasing electric field. Unlike conventional high-k gate dielectrics, such low-k organic gate dielectrics are potentially attractive for devices such as the proposed Bilayer pseudoSpin Field-Effect Transistor or flexible high speed graphene electronics.

Sanne, A.; Movva, H. C. P.; Kang, S.; McClellan, C.; Corbet, C. M.; Banerjee, S. K. [Microelectronics Research Center, University of Texas, Austin, Texas 78758 (United States)

2014-02-24T23:59:59.000Z

410

Hydrothermal synthesis of Mn vanadate nanosheets and visible-light photocatalytic performance for the degradation of methyl blue  

SciTech Connect (OSTI)

Graphical abstract: - Highlights: • Mn vanadate nanosheets have been synthesized by simple hydrothermal process. • The formation of Mn vanadate nanosheets can be controlled by growth conditions. • Mn vanadate nanosheets exhibit good photocatalytic activities for methyl blue. - Abstract: Mn vanadate nanosheets have been synthesized via a facile hydrothermal route using ammonium metavanadate and Mn acetate as the raw materials, polyvinyl pyrrolidone (PVP) as the surfactant. X-ray diffraction (XRD) shows that the Mn vanadate nanosheets are composed of monoclinic MnV{sub 2}O{sub 6} phase. Scanning electron microscopy (SEM) observation indicates that the nanosheets have the average thickness of about 50 nm, length of 2–10 ?m and width of 800 nm to 2 ?m. The growth process of the Mn vanadate nanosheets has also been discussed based on the analysis of the roles of the growth conditions on the formation of the Mn vanadate nanosheets. The nanosheets show good photocatalytic activities for the degradation of methylene blue (MB) under visible light irradiation. About 72.96% MB can be degraded after visible light irradiation for 1 h over 10 mg Mn vanadate nanosheets in 10 mL MB solution with the concentration of 10 mg L{sup ?1}.

Pei, L.Z., E-mail: lzpei@ahut.edu.cn; Xie, Y.K.; Pei, Y.Q.; Jiang, Y.X.; Yu, H.Y.; Cai, Z.Y.

2013-07-15T23:59:59.000Z

411

Modulation of DL-. alpha. -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/quisqualate receptors by phospholipase A sub 2 : A necessary step in long-term potentiation  

SciTech Connect (OSTI)

The effects of kainate (KA)-induced epileptic seizures on the binding properites of hippocampal glutamate receptors, on the modulation of DL-{alpha}-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/quisqualate receptor by phospholipase A{sub 2} (PLA{sub 2}), and on the formation of long-term potentiation (LTP) were studied in hippocampal membranes and hippocampal slices. Systemic administration of KA produced specific changes in the binding properties of the AMPA/quisqualate receptors and its regulation. Whereas the binding of various ligands to the N-methyl-D-aspartate receptors was not modified by KA treatment, there was a singificant decrease in the maximal number of binding sites for ({sup 3}H)AMPA. The loss of LTP was not due to changes in postsynaptic responses elicited by the bursts that trigger the potentiation effect, thus suggesting that KA treatment disrupts processes that follow N-methyl-D-aspartate receptor activation. Systemic administration of KA was associated with calpain activation as the amount of spectrin breakdown products was increased severalfold in hippocampus but not in cerebellum. Pretreatment of telencephalic membranes with calpain greatly reduced the PLA{sub 2}-induced increase in ({sup 3}H)AMPA binding. The results provide evidence in favor of an essential role of PLA{sub 2} in the development of LTP and suggest that the order of activation of different calcium-dependent processes is critical for producing the final changes underlying LTP.

Massicotte, G.; Baudry, M. (Univ. of Southern California, Los Angeles (United States)); Vanderklish, P.; Lynch, G. (Univ. of California, Irvine (United States))

1991-03-01T23:59:59.000Z

412

DNA methylation-dependent regulation of TrkA, TrkB, and TrkC genes in human hepatocellular carcinoma  

SciTech Connect (OSTI)

Research highlights: {yields} Expression of TrkA, TrkB, and TrkC is significantly elevated in human hepatocellular carcinoma. {yields} Downregulation of Trks is correlated with their promoter hypermethylation. {yields} Inhibiting DNA methylation restored expression of Trks in normal liver cell lines. {yields} Trks promote the proliferation of hepatocellular carcinoma. {yields} Trks induce expression of the metastatic regulator, Twist. -- Abstract: The tropomyosin-related kinase (Trk) family of neurotrophin receptors, TrkA, TrkB and TrkC, has been implicated in the growth and survival of human cancers. Here we report that Trks are frequently overexpressed in hepatocellular carcinoma (HCC) from patients and human liver cancer cell lines. To unravel the underlying molecular mechanism(s) for this phenomenon, DNA methylation patterns of CpG islands in TrkA, TrkB, and TrkC genes were examined in normal and cancer cell lines derived from liver. A good correlation was observed between promoter hypermethylation and lower expression of TrkA, TrkB, and TrkC genes, which was supported by the data that inhibiting DNA methylation with 5-azacytidine restored expression of those genes in normal liver cell lines. Furthermore, Trks promoted the proliferation of HepG2 and induced expression of the metastatic regulator, Twist. These results suggest that Trks may contribute to growth and metastasis of liver cancer.

Jin, Wook [Laboratory of Molecular Disease and Cell Regulation, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of)] [Laboratory of Molecular Disease and Cell Regulation, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of); Lee, Jong-Joo [Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)] [Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kim, Min Soo [Laboratory of Molecular Disease and Cell Regulation, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of)] [Laboratory of Molecular Disease and Cell Regulation, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon (Korea, Republic of); Son, Byung Ho [Department of Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, 108 Pyung-dong, Jongro-gu, Seoul 110-746 (Korea, Republic of)] [Department of Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, 108 Pyung-dong, Jongro-gu, Seoul 110-746 (Korea, Republic of); Cho, Yong Kyun, E-mail: choyk2004@hanmail.net [Division of Gastroenterology, Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University, School of Medicine, 108 Pyung-dong, Jongro-gu, Seoul 110-746 (Korea, Republic of); Kim, Hyoung-Pyo, E-mail: kimhp@yuhs.ac [Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)] [Department of Environmental Medical Biology, Institute of Tropical Medicine, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

2011-03-04T23:59:59.000Z

413

Supramolecular Catalysis of Orthoformate Hydrolysis in Basic Solution: An Enzyme-Like Mechanism  

SciTech Connect (OSTI)

Magnetic susceptibility measurements and X-ray data confirm that tert-butyl substituted manganocenes [(Me{sub 3}C){sub n}C{sub 5}H{sub 5-n}]{sub 2}Mn (n= 1, 2) follow the trend previously observed with the methylated manganocenes, i.e., electron donating groups attached to the Cp ring stabilize the low-spin (LS) electronic ground state relative to Cp{sub 2}Mn and exhibit higher spin-crossover (SCO) temperatures. However, introducing three CMe3 groups on each ring gives a temperature invariant high-spin (HS) state manganocene. The origin of the high-spin state in [1,2,4-(Me{sub 3}C){sub 3}C{sub 5}H{sub 2}]{sub 2}Mn is due to the significant bulk of the [1,2,4-(Me{sub 3}C){sub 3}C{sub 5}H{sub 2}]{sup -} ligand, which is sufficient to generate severe inter-ring steric strain that prevents the realization of the low-spin state. Interestingly, the spin transition in [1,3-(Me{sub 3}C){sub 2}C{sub 5}H{sub 3}]{sub 2}Mn is accompanied by a phase transition resulting in a significant irreversible hysteresis ({Delta}T{sub c} = 16 K). This structural transition was also observed by extended X-ray absorption fine-structure (EXAFS) measurements. Magnetic susceptibility studies and X-ray diffraction data on SiMe{sub 3} substituted manganocenes [(Me{sub 3}Si){sub n}C{sub 5}H{sub 5-n}]{sub 2}Mn (n= 1, 2, 3) show high-spin configuration in these cases. Although tetra- and hexasubstituted manganocenes are high-spin at all accessible temperatures, the disubstituted manganocenes exhibit a small low-spin admixture at low temperature. In this respect it behaves similarly to [(Me{sub 3}C)(Me{sub 3}Si)C{sub 5}H{sub 3}]{sub 2}Mn, which has a constant low-spin admixture up to 90 K and then gradually converts to high-spin. Thermal spin-trapping can be observed for [(Me{sub 3}C)(Me{sub 3}Si)C{sub 5}H{sub 3}]{sub 2}Mn on rapid cooling.

Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

2008-04-17T23:59:59.000Z

414

Sodalite ion exchange in polyethylene oxide oligomer solvents Gina M. Canfield,a  

E-Print Network [OSTI]

Sodalite ion exchange in polyethylene oxide oligomer solvents Gina M. Canfield,a Michael Bizimisb and rare earth ions. Ethylene oxide-based oligomers (polyethylene glycol, polyethylene glycol methyl ether

Latturner, Susan

415

APPENDXD.CHP:Corel VENTURA  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

Report The Form EIA-819, "Monthly Oxygenate Report" provides production data for fuel ethanol and methyl tertiary butyl ether (MTBE). End-of-month stock data held at ethanol...

416

EAST CAROLINA UNIVERSITY HAZARDOUS CHEMICAL USE GRANT REVIEW FORM ECU policy requires that all grant proposals involving the use of hazardous chemicals be reviewed by an institutional review committee or  

E-Print Network [OSTI]

-benezene 4-Aminodiphenyl Asbestos Coal tar pitch volatiles Methyl chloromethyl ether Formaldehyde Vinyl chloride Coke oven emissions 1,2-dibromo-3-chloropropane Lead Cadmium Benzene Cotton dust Chromium VI

417

A Low-Carbon Fuel Standard for California Part 1: Technical Analysis  

E-Print Network [OSTI]

methyl-tertiary butyl ether (MTBE), from gasoline by 2004.MTBE was used to meet a requirement for gasoline to containbeginning in 2002, replacing MTBE with ethanol. According to

2007-01-01T23:59:59.000Z

418

Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity  

E-Print Network [OSTI]

methyl-tertiary-butyl- ether (MTBE) and the biomass burningfrom all source categories. MTBE is a gasoline additive andwith the fuel tracer MTBE (e.g. 0.82 for MTBE/benzene).

Karl, T.; Apel, E.; Hodzic, A.; Riemer, D. D; Blake, D. R; Wiedinmyer, C.

2009-01-01T23:59:59.000Z

419

Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area  

E-Print Network [OSTI]

Methanol Ethanol Acetone MEK MTBE CO Methane UCI UCI TOGA/methyl tertiary butyl ether (MTBE), and toluene all ratioedthe observed decay. For MTBE, also a species that is not

2010-01-01T23:59:59.000Z

420

Soil type, crop and irrigation technique affect nitrogen leaching to groundwater  

E-Print Network [OSTI]

water contamination with MTBE (methyl tertiary-butyl ether,that areas vulnerable to MTBE are also vulner- able tothat affect the movement of MTBE. If only a small amount of

Letey, John; Vaughan, Peter

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Characterization of trace gases measured over Alberta oil sands mining operations: 76 speciated C2-C10 volatile organic compounds (VOCs), CO2, CH4, CO, NO, NO2, NOy, O3 and SO2  

E-Print Network [OSTI]

methyl tertiary- butyl ether (MTBE) and its effect on plasmaand three VOCs (propyne, furan, MTBE) remained below their 3Ethanol Acetone MEK MAC MVK MTBE Furan CH 3 OH C 2 H 5 OH C

2010-01-01T23:59:59.000Z

422

A Low-Carbon Fuel Standard for California, Part 1: Technical Analysis  

E-Print Network [OSTI]

methyl-tertiary butyl ether (MTBE), from gasoline by 2004.MTBE was used to meet a requirement for gasoline to containbeginning in 2002, replacing MTBE with ethanol. According to

Farrell, Alexander E.; Sperling, Dan

2007-01-01T23:59:59.000Z

423

Factors influencing biological treatment of MTBE contaminated ground water  

E-Print Network [OSTI]

Methyl tertiary-butyl ether (MTBE) biodegradation in batchCometabolic degradation of MTBE by a cyclohexane-oxidizingof 49 Biological Treatment of MTBE Fortin, N. Y. , and M. A.

Stringfellow, William T.; Hines Jr., Robert D.; Cockrum, Dirk K.; Kilkenny, Scott T.

2001-01-01T23:59:59.000Z

424

Finding the missing stratospheric Bry: a global modeling study of CHBr3 and CH2Br2  

E-Print Network [OSTI]

Methanol Ethanol Acetone MEK MTBE CO Methane UCI UCI TOGA/methyl tertiary butyl ether (MTBE), and toluene all ratioedthe observed decay. For MTBE, also a species that is not

2010-01-01T23:59:59.000Z

425

Life-Cycle Water Impacts of U.S. Transportation Fuels  

E-Print Network [OSTI]

Drinking Water: Methyl Tertiary Butyl Ether (MTBE).http://www.epa.gov/mtbe/water.htm (11/30/10), Chiu, Y. W. ;LCFS LCI LP LPG MED MRO MSF MTBE MWD MWDOC NAICS NERC NETL

Scown, Corinne Donahue

2010-01-01T23:59:59.000Z

426

Electrodeposition of nickel-aluminum alloys from the aluminum chloride-1-methyl-3-ethylimidazolium chloride room temperature molten salt  

SciTech Connect (OSTI)

The electrodeposition of Ni and Ni-Al alloys on glassy carbon was investigated in the 66.7--33.3 mole percent (m/o) Al chloride-1-methyl-3-ethylimidazolium chloride molten salt containing electrogenerated Ni(II) at 40 C. The electrodeposition of Ni on glassy carbon involves 3-D progressive nucleation on a finite number of active sites with hemispherical diffusion-controlled growth of the nuclei. At potentials slightly more negative than those needed to induce the reduction of Ni(II) to the metal, Al is codeposited with Ni to produce Ni-Al alloys. Controlled-potential and controlled-current experiments revealed that it is possible to produce alloy deposits containing up to approximately 40 atomic percent (a/o) Al under conditions that circumvent the bulk deposition of Al. The Al content of the Ni-Al deposit was found to vary linearly with the deposition potential but nonlinearly with the current density. The electrodeposited Ni-Al alloys are thermodynamically unstable with respect to Ni(II), i.e., immersion of the alloy deposit in melt containing Ni(II) under open-circuit conditions leads to a reduction in the Al content of the alloy. The mechanism of alloy formation appears to involve underpotential deposition of Al on the developing Ni deposit; however, alloy formation must be kinetically hindered because the Al content is always less than predicted from theoretical considerations. Ni-Al alloys produced at 0.30 V in melt containing Ni(II) and 20% (w/w) benzene as a cosolvent contained about 15 a/o Ni and were of high quality with a disordered fcc structure, but alloys produced at more negative potentials had the visual appearance of a loosely adherent, finely divided, black powder and were heavily contaminated with chloride, probably as a result of the occlusion of the molten salt solvent by the dendritic alloy deposit during deposit growth.

Pitner, W.R.; Hussey, C.L. [Univ. of Mississippi, University, MS (United States). Dept. of Chemistry; Stafford, G.R. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Materials Science and Engineering Lab.

1996-01-01T23:59:59.000Z

427

Mode of action of ethyl tertiary-butyl ether hepatotumorigenicity in the rat: Evidence for a role of oxidative stress via activation of CAR, PXR and PPAR signaling pathways  

SciTech Connect (OSTI)

To elucidate possible mode of action (MOA) and human relevance of hepatotumorigenicity in rats for ethyl tertiary-butyl ether (ETBE), male F344 rats were administered ETBE at doses of 0, 150 and 1000 mg/kg body weight twice a day by gavage for 1 and 2 weeks. For comparison, non-genotoxic carcinogen phenobarbital (PB) was applied at a dose of 500 ppm in diet. Significant increase of P450 total content and hydroxyl radical levels by low, high doses of ETBE and PB treatments at weeks 1 and 2, and 8-OHdG formation at week 2, accompanied accumulation of CYP2B1/2B2, CYP3A1/3A2 and CYP2C6, and downregulation of DNA oxoguanine glycosylase 1, induction of apoptosis and cell cycle arrest in hepatocytes, respectively. Up-regulation of CYP2E1 and CYP1A1 at weeks 1 and 2, and peroxisome proliferation at week 2 were found in high dose ETBE group. Results of proteome analysis predicted activation of upstream regulators of gene expression altered by ETBE including constitutive androstane receptor (CAR), pregnane-X-receptor (PXR) and peroxisome proliferator-activated receptors (PPARs). These results indicate that the MOA of ETBE hepatotumorigenicity in rats may be related to induction of oxidative stress, 8-OHdG formation, subsequent cell cycle arrest, and apoptosis, suggesting regenerative cell proliferation after week 2, predominantly via activation of CAR and PXR nuclear receptors by a mechanism similar to that of PB, and differentially by activation of PPARs. The MOA for ETBE hepatotumorigenicity in rats is unlikely to be relevant to humans. - Highlights: • We focus on MOA and human relevance of hepatotumorigenicity in rats for ETBE. • ETBE was administered to F344 rats for 1 and 2 weeks. • Oxidative stress formation, proliferation and apoptosis in the liver are analyzed. • ETBE-induced changes of gene and protein expression in the liver are examined. • The effects are compared with those induced by non-genotoxic carcinogen PB.

Kakehashi, Anna, E-mail: anna@med.osaka-cu.ac.jp [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585 (Japan); Hagiwara, Akihiro; Imai, Norio [DIMS Institute of Medical Science, Inc., 64 Goura, Nishiazai, Azai-cho, Ichinomiya, Aichi 491-0113 (Japan); Nagano, Kasuke [Nagano Toxicologic-Pathology Consulting, Ochiai, Hadano, Kanagawa 257-0025 (Japan); Nishimaki, Fukumi [Biofuel Assessment Group, New Fuels Dept., Japan Petroleum Energy Center (JPEC), 4-3-9 Toranomon, Minato-ku, Tokyo 105-0001 (Japan); Banton, Marcy [Toxicology and Risk Assessment, LyondellBasell Industries, LyondellBasell Corporate HSE/Product Safety, One Houston Center, Suite 700, 1221 McKinney Street, Houston, TX 770 10 (United States); Wei, Min [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585 (Japan); Fukushima, Shoji [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585 (Japan); Japan Bioassay Research Center, Japan Industrial Safety and Health Association, 2445 Hirasawa, Hadano, Kanagawa 257-0011 (Japan); Wanibuchi, Hideki [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585 (Japan)

2013-12-01T23:59:59.000Z

428

Polybrominated dibenzo-p-dioxins/dibenzofurans and polybrominated diphenyl ethers in soil, vegetation, workshop-floor dust, and electronic shredder residue from an electronic waste recycling facility and in soils from a chemical industrial complex in eastern China  

SciTech Connect (OSTI)

In this study, 11 2,3,7,8-substituted PBDD/Fs and 10 polybrominated diphenyl ether (PBDE) congeners were determined in electronic shredder waste, workshop-floor dust, soil, and leaves (of plants on the grounds of the facility) from a large-scale electronic wastes (e-waste) recycling facility and in surface soil from a chemical-industrial complex (comprising a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant) as well as agricultural areas in eastern China. Total PBDD/F concentrations in environmental samples were in the range of 113-818 pg/g dry wt (dw) for leaves, 392-18,500 pg/g dw for electronic shredder residues, 716-80,0000 pg/g dw for soil samples, and 89,600-14,3000 pg/g dw for workshop-floor dust from the e-waste recycling facility and in a range from nondetect (ND) to 427 pg/g dw in soil from the chemical-industrial complex. The highest mean concentrations of total PBDD/Fs were found in soil samples and workshop-floor dust from the e-waste recycling facility. The dioxin-like toxic equivalent (measured as TEQ) concentrations of PBDD/Fs were greater than the TEQs of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) reported in our previous study for the same set of samples. The concentrations of PBDFs were several orders of magnitude higher than the concentrations of PBDDs in samples from the e-waste facility or from soil from the chemical-industrial complex. A significant correlation was found between the concentrations of {Sigma}PBDD/Fs and {Sigma}PBDEs (r = 0.769, p < 0.01) and between SPBDD/Fs and the previously reported SPCDD/F concentrations (r = 0.805, p < 0.01). The estimated daily human intakes of TEQs contributed by PBDD/Fs via soil/dust ingestion and dermal exposures in e-waste recycling facilities were higher than the intakes of TEQs contributed by PCDD/Fs, calculated in our previous study. 45 refs., 2 figs., 2 tabs.

Jing Ma; Rudolf Addink; Sehun Yun; Jinping Cheng; Wenhua Wang; Kurunthachalam Kannan [Shanghai Jiao Tong University, Shanghai (China). School of Environmental Science and Engineering

2009-10-01T23:59:59.000Z

429

amine methanol, ether . Amine amine CO2  

E-Print Network [OSTI]

, . promoter . 1.2 CO2 HBGS process CO2 , CO2 . CO2 , IGCC (Integrated Gasification Combined Cycle) (fuel gas) CO2 . IGCC CO2 H2 . (gasification) CO H2 (water gas shift reaction) H2 CO CO2 . CO2 H2 turbine H2 . H2 , CO2 #12;. fuel gas CO2 40%, 60% H2 . fuel gas (gasification) HBGS process . CO2 CO2 . venture

Hong, Deog Ki

430

Analytical Methodologies for Detection of Gamma-Valerolactone, Delta-Valerolactone, Acephate and Azinphos Methyl and Their Associated Metabolites in Complex Biological Matrices  

SciTech Connect (OSTI)

Non-invasive biomonitoring for chemicals of interest in law enforcement and similar monitoring of pesticides, together with their metabolites, can not only save money but can lead to faster medical attention for individuals exposed to these chemicals. This study describes methods developed for the analysis of gamma-valerolactone (GVL), delta-valerolactone (DVL), acephate, and azinphos methyl in saliva and serum. Liquid chromatography/mass spectrometry (LC/MS) operated in the negative and positive ion mode and gas chromatography/mass spectrometry (GC/MS) were used to analyze GVL and DVL. Although both analytical techniques worked well, lower detection limits were obtained with GC/MS. The lactones and their corresponding sodium salts were spiked into both saliva and serum. The lactones were isolated from saliva or serum using newly developed extraction techniques and then subsequently analyzed using GC/MS. The sodium salts of the lactones are nonvolatile and require derivatization prior to analysis by this method. N-methyl-N-(t-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) was ultimately selected as the reagent for derivatization because the acidic conditions required for reactions with diazomethane caused the salts to undergo intramolecular cyclization to the corresponding lactones. In vitro studies were conducted using rat liver microsomes to determine other metabolites associated with these compounds. Azinphos methyl and acephate are classified as organophosphate pesticides, and are known to be cholinesterase inhibitors in humans and insects, causing neurotoxicity. For this reason they have both exposure and environmental impact implications. These compounds were spiked into serum and saliva and prepared for analysis by GC/MS. Continuation of this research would include analysis by GC/MS under positive ion mode to determine the parent ions of the unknown metabolites. Further research is planned through an in vivo analysis of the lactones and pesticides. These methodologies could be extended for further analysis of other similar compounds.

Zink, E.; Clark, R.; Grant, K.; Campbell, J.; Hoppe, E.

2005-01-01T23:59:59.000Z

431

Controlling DNA Methylation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed New SubstationCleanCommunity2Workshops01 SF-30Innovationin Vapor-Liquid-Solid

432

Dissociation of internal energy-selected methyl bromide ion revealed from threshold photoelectron-photoion coincidence velocity imaging  

SciTech Connect (OSTI)

Dissociative photoionization of methyl bromide (CH{sub 3}Br) in an excitation energy range of 10.45–16.90 eV has been investigated by using threshold photoelectron-photoion coincidence (TPEPICO) velocity imaging. The coincident time-of-flight mass spectra indicate that the ground state X{sup 2}E of CH{sub 3}Br{sup +} is stable, and both A{sup 2}A{sub 1} and B{sup 2}E ionic excited states are fully dissociative to produce the unique fragment ion of CH{sub 3}{sup +}. From TPEPICO 3D time-sliced velocity images of CH{sub 3}{sup +} dissociated from specific state-selected CH{sub 3}Br{sup +} ion, kinetic energy release distribution (KERD) and angular distribution of CH{sub 3}{sup +} fragment ion are directly obtained. Both spin-orbit states of Br({sup 2}P) atom can be clearly observed in fast dissociation of CH{sub 3}Br{sup +}(A{sup 2}A{sub 1}) ion along C–Br rupture, while a KERD of Maxwell-Boltzmann profile is obtained in dissociation of CH{sub 3}Br{sup +}(B{sup 2}E) ion. With the aid of the re-calculated potential energy curves of CH{sub 3}Br{sup +} including spin-orbit coupling, dissociation mechanisms of CH{sub 3}Br{sup +} ion in A{sup 2}A{sub 1} and B{sup 2}E states along C–Br rupture are revealed. For CH{sub 3}Br{sup +}(A{sup 2}A{sub 1}) ion, the CH{sub 3}{sup +} + Br({sup 2}P{sub 1/2}) channel is occurred via an adiabatic dissociation by vibration, while the Br({sup 2}P{sub 3/2}) formation is through vibronic coupling to the high vibrational level of X{sup 2}E state followed by rapid dissociation. C–Br bond breaking of CH{sub 3}Br{sup +}(B{sup 2}E) ion can occur via slow internal conversion to the excited vibrational level of the lower electronic states and then dissociation.

Tang, Xiaofeng [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China) [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Zhou, Xiaoguo, E-mail: xzhou@ustc.edu.cn, E-mail: yanbing@jlu.edu.cn; Liu, Shilin [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China) [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Sun, Zhongfa [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China)] [Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Liu, Fuyi; Sheng, Liusi [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)] [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Yan, Bing, E-mail: xzhou@ustc.edu.cn, E-mail: yanbing@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)] [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)

2014-01-28T23:59:59.000Z

433

Properties of electrospun CdS and CdSe filled poly(methyl methacrylate) (PMMA) nanofibres  

SciTech Connect (OSTI)

Graphical abstract: SEM images of CdS/PMMA showing coiling as loading of CdS nanoparticles is increased. Thermal stability is increased with increase in %loading of both CdS and CdSe nanoparticles. Research highlights: {yields} TOPO-capped CdS and HDA-capped CdSe nanoparticles were synthesized and fully characterized. {yields} The nanoparticles were mixed with the polymer, PMMA using electrospinning technique using 2, 5 and 10% weight loadings. {yields} The mixture was spun to produce fibres with optical and thermal properties showing significant change and also the increase in loading causing bending or spiraling. {yields} Both TEM images for nanoparticles and SEM for fibres shows the morphology and sizes of the particles. -- Abstract: Electrospinning technique was used to fabricate poly(methyl methacrylate) (PMMA) fibres incorporating CdS and CdSe quantum dots (nanoparticles). Different nanoparticle loadings (2, 5 and 10 wt% with respect to PMMA) were used and the effect of the quantum dots on the properties of the fibres was studied. The optical properties of the hybrid composite fibres were investigated by photoluminescence and UV-vis spectrophotometry. Scanning electron microscopy (SEM), X-ray diffraction and FTIR spectrophotometry were also used to investigate the morphology and structure of the fibres. The optical studies showed that the size-tunable optical properties can be achieved in the polymer fibres by addition of quantum dots. SEM images showed that the morphologies of the fibres were dependent on the added amounts of quantum dots. A spiral type of morphology was observed with an increase in the concentration of CdS and CdSe nanoparticles. Less beaded structures and bigger diameter fibres were obtained at higher quantum dot concentrations. X-ray diffractometry detected the amorphous peaks of the polymer and even after the quantum dots were added and the FTIR analysis shows that there was no considerable interaction between the quantum dots and the polymer fibres at low concentration of quantum dots however at higher concentrations some interactions were observed which shows that QDs were present on the surfaces of the fibres.

Mthethwa, T.P. [University of Johannesburg, Department of Chemical Technology, P.O. Box 17011, Doornfontein 2028 (South Africa)] [University of Johannesburg, Department of Chemical Technology, P.O. Box 17011, Doornfontein 2028 (South Africa); Moloto, M.J., E-mail: mmoloto@uj.ac.za [University of Johannesburg, Department of Chemical Technology, P.O. Box 17011, Doornfontein 2028 (South Africa); De Vries, A.; Matabola, K.P. [CSIR Materials Science and Manufacturing, 4 Gomery avenue, Summerstrand, Port Elizabeth 6000 (South Africa)] [CSIR Materials Science and Manufacturing, 4 Gomery avenue, Summerstrand, Port Elizabeth 6000 (South Africa)

2011-04-15T23:59:59.000Z

434

Electronic and optical response of Ru(II) complexes functionalized by methyl, carboxylate groups: joint theoretical and experimental study  

SciTech Connect (OSTI)

New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the complex to the surface of a semiconductor, a linking bridge - a carboxyl group - is added to one or two of the 2,2{prime}-bipyridine ligands. Such changes in the ligand structure, indeed, affect electronic and optical properties and consequently, the charge transfer reactivity of Ru-systems. In this study, we apply both theoretical and experimental approaches to analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the Ru(II) bipyridine complex. First principle calculations based on density functional theory (DFT) and linear response time dependent density functional theory (TDDFT) are used to simulate the ground and excited-state structures of functionalized Ru-complexes in the gas phase, as well as in acetonitrile solution. In addition, an inelaborate Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states. All theoretical results nicely complement experimental absorption spectra of Ru-complexes and contribute to their interpretation. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show a high probability of deprotonation of the carbboxyl group in the Ru-complexes resulted in a slight blue shift and decrease of intensities of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotanated complexes demonstrate strong agreement when acetonitrile solvent is used in simulations. A polar solvent is found to play an important role in calculations of optical spectra: it stabilizes the energy of states localized on the carboxyl or carboxylate groups eliminating artificial charge transport states, which typically appear in TDDFT calculations. Thus, it is validated that the excited-state structure of the functionalized Ru-complexes, specifically in the case of the deprotonated functions, can be accurately modeled by TDDFT with the addition of a dielectric continuum in simulations.

Tretiak, Sergei [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

435

Murine T cell activation is regulated by surfen (bis-2-methyl-4-amino-quinolyl-6-carbamide)  

SciTech Connect (OSTI)

Highlights: •Surfen is the first inhibitor of glycosaminoglycan function to be studied in murine T cells. •Surfen reduces T cell proliferation stimulated in vitro and in vivo. •Surfen reduces CD25 expression in T cells activated in vivo but not in vitro. •Surfen increases T cell proliferation when T cell receptor activation is bypassed. •Surfen’s effects are blocked by co-administration of heparin sulfate. -- Abstract: Surfen (bis-2-methyl-4-amino-quinolyl-6-carbamide) binds to glycosaminoglycans (GAGs) and has been shown to influence their function, and the function of proteoglycans (complexes of GAGs linked to a core protein). T cells synthesize, secrete and express GAGs and proteoglycans which are involved in several aspects of T cell function. However, there are as yet no studies on the effect of GAG-binding agents such as surfen on T cell function. In this study, surfen was found to influence murine T cell activation. Doses between 2.5 and 20 ?M produced a graduated reduction in the proliferation of T cells activated with anti-CD3/CD28 antibody-coated T cell expander beads. Surfen (20 mg/kg) was also administered to mice treated with anti-CD3 antibody to activate T cells in vivo. Lymphocytes from surfen-treated mice also showed reduced proliferation and lymph node cell counts were reduced. Surfen reduced labeling with a cell viability marker (7-ADD) but to a much lower extent than its effect on proliferation. Surfen also reduced CD25 (the ?-subunit of the interleukin (IL)-2 receptor) expression with no effect on CD69 expression in T cells treated in vivo but not in vitro. When receptor activation was bypassed by treating T cells in vitro with phorbyl myristate acetate (10 ng/ml) and ionomycin (100 ng/ml), surfen treatment either increased proliferation (10 ?M) or had no effect (2.5, 5 and 20 ?M). In vitro treatment of T cells with surfen had no effect on IL-2 or interferon-? synthesis and did not alter proliferation of the IL-2 dependent cell line CTLL-2. The effect of surfen was antagonized dose-dependently by co-treatment with heparin sulfate. We conclude that surfen inhibits T cell proliferation in vitro and in vivo. When T cell receptor-driven activation is bypassed surfen had a neutral or stimulatory effect on T cell proliferation. The results imply that endogenous GAGs and proteoglycans play a complex role in promoting or inhibiting different aspects of T cell activation.

Warford, Jordan, E-mail: jordan.warford@dal.ca [Department of Pathology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada)] [Department of Pathology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Doucette, Carolyn D., E-mail: carolyn.doucette@dal.ca [Department of Microbiology and Immunology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Hoskin, David W., E-mail: d.w.hoskin@dal.ca [Department of Pathology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Microbiology and Immunology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Easton, Alexander S., E-mail: alexander.easton@dal.ca [Department of Pathology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Microbiology and Immunology, Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada); Department of Surgery (Neurosurgery), Dalhousie University, Tupper Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2 (Canada)

2014-01-10T23:59:59.000Z

436

New etherification process commercialized in Finland  

SciTech Connect (OSTI)

The phase-out of leaded fuels in Europe, Asia, and parts of Africa and Latin America is increasing demand for octane and octane-bearing fuel components such as ethers. Early solutions to the problem of increasing octane while reducing tailpipe emissions involved use of methyl tertiary butyl ether (MTBE). According to Neste, using both tertiary amyl methyl ether (TAME) and MTBE can give refiners increased blending flexibility for volatility control. But the economics associated with TAME production often make TAME units difficult to justify. The paper discusses the NExTAME process, the unit at the Porvoo refinery and process improvements.

NONE

1997-01-06T23:59:59.000Z

437

Possible modulation of N-methyl-D,L-aspartic acid induced prolactin release by testicular steroids in the adult male rhesus monkey  

SciTech Connect (OSTI)

N-methyl-D,L-aspartic acid (NMA), an agonist of the neurotransmitter glutamate has been shown to acutely stimulate the release of prolactin (PRL) in intact rats and monkeys. To further investigate the role of neuroexcitatory amino acids in PRL secretion, the effects of NMA administration were examined on PRL release in long term orchidectomized adult rhesus monkeys, in both the absence and presence of testosterone. Intact and long term castrated adult male monkeys weighing between 8-13 kg, were implanted with a catheter via the saphenous vein for blood withdrawal and drug infusion. Blood samples were collected at 10 min intervals for 50 min before and 70 min after administration of the drug or vehicle. Plasma PRL concentrations were estimated using radioimmunoassay. Whereas a single iv injection of NMA induced a prompt discharge of PRL in intact monkeys, an identical dose had surprisingly no effect on PRL secretion in orchidectomized animals. On the other hand, plasma PRL increases in response to a challenge dose of thyrotropin releasing hormone were similar in magnitude in the two groups of monkeys. Testosterone replacement in orchidectomized animals by parenteral administration of testosterone enanthate reinitiated the PRL responsiveness to acute NMA stimulation. These results indicate that N-methyl-D-aspartic acid (NMDA) dependent drive to PRL release in the adult male rhesus monkey may be overtly influenced by the sex steroid milieu.

Arslan, M.; Rizvi, S.S.R.; Jahan, S.; Zaidi, P.; Shahab, M. (Quaid-i-Azam Univ., Islamabad (Pakistan))

1991-01-01T23:59:59.000Z

438

Synthesis of 6-Methyl-9-propyldibenzothiophene-4-ol amended to 9-isopropyl-6-methyldibenzothiophene-4-ol. Final technical report, July 25, 1991--January 25, 1993  

SciTech Connect (OSTI)

This is a draft final technical report on Task 1 of a contract to synthesize 6-Methyl-9-propyldibenzothiophene-4-ol, as amended to 9- isopropyl-6-methyldibenzothiophene-4-ol. This report is a compilation of data presented in earlier reports. The first annual report dealt with an attempted synthesis of 4-methoxy-6-methyl-9- propyldibenzothiophene (the original target compound), the successful synthesis and delivery of 200 grams of the sulfide 1,4-diethyl-2- [(2{prime}-methoxyphenyl)-thio]benzene, and initial work on a new synthesis route for the preparation of the new target compound 9- isopropyl-6-methyldibenzothiophene-4-ol. The change to the new target compound and the new synthesis route became necessary when it was learned that the sulfide mixture could not be cyclized to the substituted dibenzothiophene mixture. The second annual report described the successful preparation of 45 g of the new target compound using the new synthesis route. Subsequently funds were provided to synthesize an additional 45 g of the new target using the same reaction scheme. This task was recently completed.

Eisenbraun, E.J.

1992-02-17T23:59:59.000Z

439

Oxygenates du`jour...MTBE? Ethanol? ETBE?  

SciTech Connect (OSTI)

There are many different liquids that contain oxygen which could be blended into gasoline. The ones that have been tried and make the most sense are in the alcohol (R-OH) and ether (R-O-R) chemical family. The alcohols considered are: methanol (MeOH), ethanol (EtOH), tertiary butyl alcohol (TBA). The ethers are: methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary amyl ethyl ether (TAEE), di-isopropyl ether (DIPE). Of the eight oxygenates listed above, the author describes the five that are still waiting for widespread marketing acceptance (methanol, TBA, TAME, TAEE, and DIPE). He then discusses the two most widely used oxygenates in the US, MTBE and ethanol, along with the up-and-coming ethanol ether, ETBE. Selected physical properties for all of these oxygenates can be found in Table 2 at the end of this paper. A figure shows a simplified alcohol/ether production flow chart for the oxygenates listed above and how they are interrelated.

Wolfe, R.

1995-12-31T23:59:59.000Z

440

Synthesis and characterization of redox polymers of (M(4-vinyl-4 prime -methyl-2,2 prime -bipyridine) sub 3 )(PF sub 6 ) sub 2 (M = Ru, Os)  

SciTech Connect (OSTI)

The authors have prepared polymers of (M(vbpy){sub 3}(PF{sub 6}){sub 2}) (M = Ru, Os) (vbpy = 4-vinyl-4{prime}-methyl-2,2{prime}-bipyridine) in solution via free-radical polymerization and fractionated them according to molecular weight using size exclusion chromatography. Different fractions have been characterized by electrochemical and spectroscopic means. The authors find that whereas for the osmium containing polymers the relative polymer size varies in proportion to the number of vinyl groups consumed during the polymerization reaction, the same is not true for the analogous ruthenium polymers. In addition, the emission energy of both the ruthenium and osmium polymers is also related to the concentration of residual vinyl groups in the polymer. Upon polymerization, there is a shift in the emission toward higher energies. Electrochemically determined diffusion coefficients are consistent with the relative size of the various fractions.

Bommarito, S.L.; Lowery-Bretz, S.P.; Abruna, H.D. (Cornell Univ., Ithaca, NY (United States))

1992-02-05T23:59:59.000Z

Note: This page contains sample records for the topic "methyl tert-butyl ether" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Thermally Switchable Thin Films of an ABC Triblock Copolymer of Poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate)  

SciTech Connect (OSTI)

The thermo-responsive behavior of polymer films consisting of novel linear triblock copolymers of poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate) (PnBuMA-PMMA-P2FEMA) are reported using differential scanning calorimetry (DSC), atomic forcing microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contacting angle (CA) measurements. The surface morphology, wettability and chemical structure of thin films of these triblock copolymers on silicon wafers as a function of temperature have been investigated. It has been shown that the wettability of the films is thermally switchable. Detailed structural analysis shows that thermo-responsive surface composition changes are produced. The underlying mechanism of the thermoresponsive behavior is discussed.

Zhang, Shanju [Georgia Institute of Technology; Liu, Zhan [Georgia Institute of Technology; Bucknall, David G. [Georgia Institute of Technology; He, Lihong [ORNL; Hong, Kunlun [ORNL; Mays, Jimmy [ORNL; Allen, Mark [Georgia Institute of Technology

2011-01-01T23:59:59.000Z

442

Synthesis and characterization of redox copolymers of (Ru(4-vinyl-4 prime -methyl-2,2 prime -bipyridine) sub 3 ) sup 2+ and (Os(4-vinyl-4 prime -methyl-2,2 prime -bipyridine) sub 3 ) sup 2+ : Unusual energy-transfer dynamics  

SciTech Connect (OSTI)

Copolymers of (Ru(vbpy){sub 3}(PF{sub 6}){sub 2}) and (Os(vbpy){sub 3}(PF{sub 6}){sub 2}) (vbpy = 4-vinyl-4{prime}-methyl-2,2{prime}-bipyridine) have been prepared in solution and by electropolymerization. The ruthenium and osmium monomers were incorporated in the copolymers in different ratios depending on the polymerization method. These results point to fundamental differences between solution polymerization and electropolymerization. In addition, luminescence experiments at liquid-nitrogen temperature and room temperature point to a significant degree of energy transfer from ruthenium to osmium states in the polymer.

Bommarito, S.L.; Lowery-Bretz, S.P.; Abruna, H.D. (Cornell Univ., Ithaca, NY (United States))

1992-02-05T23:59:59.000Z

443

Methyl chloride via oxyhydrochlorination of methane: A building block for chemicals and fuels from natural gas. Quarterly technical progress report No. 01, September 30, 1996--December 31, 1996  

SciTech Connect (OSTI)

The objectives of this cooperative agreement are to develop the oxyhydrochlorination (OHC) process for the conversion of methane to methyl chloride. In the first Phase of the project, Dow Corning has developed a stable selective catalyst and demonstrated the technology on a laboratory and a pilot plant scale. Specific tasks to achieve these objectives have been developed as follows: TASK 1 Fundamental Technical and Economic Evaluation TASK 2 Catalyst Selection Optimization and Characterization Studies TASK 3 Pilot Plant Design TASK 4 Pilot Plant Detailed Engineering, Procurement and Construction TASK 5 Pilot Plant Startup and Operation TASK 6 Pilot Plant Process Optimization TASK 7 Pilot Plant Extended Operation TASK 8 Pilot Plant Economic Evaluation/Scale-up Decision Significant progress has been completed in Task 1 with the objective to complete a fundamental technical and economic evaluation of learning gathered the Phase I effort of this project. A decision to proceed with the project will be made after completion of this Task. A computer model of the reactor system has been developed, which includes heat and mass transfer effects as well as reactions. Model validation is in progress. The Absorber/Stripper technology evaluated and implemented on the Phase I PDU to recover chlorocarbons (including methyl chloride) from reaction products has been scaled to evaluate economics for a commercial scale plant. In a parallel exercise, alternate recovery technologies were investigated for economic evaluation, to assure that the minimum capital option is pursued for the Phase II design. Commercial scale plant equipment and total plant costs are being evaluated using information from the Phase I PDU, reactor modeling and recovery system evaluation to estimate capital and operating costs for a commercial scale OHC unit.

Wineland, J.

1997-01-16T23:59:59.000Z

444

Pdybedron Vol. 7. No. 19/20, pp. 200-2008, 1988 Printed in Great Britain  

E-Print Network [OSTI]

is bonded to four lithium atoms, and there are Li ... H-C interactions with two of the methyl groups-Alkylation of Mn(acac)s (acac = 2,4_pentanedionato) with five equiv. of methyl- lithium in diethyl ether, followedOMe:-1, which has been isolated as a lithium double salt with the 4-methyl-2-penten-2,4_diolate (Meacac

Girolami, Gregory S.

445

Pharmacological characterization of LY233053: A structurally novel tetrazole-substituted competitive N-methyl-D-aspartic acid antagonist with a short duration of action  

SciTech Connect (OSTI)

This study reports the activity of a structurally novel excitatory amino acid receptor antagonist, LY233053 (cis-(+-)-4-((2H-tetrazol-5-yl)methyl)piperidine-2-carboxylic acid), the first tetrazole-containing competitive N-methyl-D-aspartic acid (NMDA) antagonist. LY233053 potently inhibited NMDA receptor binding to rat brain membranes as shown by the in vitro displacement of (3H) CGS19755 (IC50 = 107 +/- 7 nM). No appreciable affinity in (3H)alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) or (3H)kainate binding assays was observed (IC50 values greater than 10,000 nM). In vitro NMDA receptor antagonist activity was further demonstrated by selective inhibition of NMDA-induced depolarization in cortical wedges (IC50 = 4.2 +/- 0.4 microM vs. 40 microM NMDA). LY233053 was effective after in vivo systemic administration in a number of animal models. In neonatal rats, LY233053 selectively blocked NMDA-induced convulsions (ED50 = 14.5 mg/kg i.p.) with a relatively short duration of action (2-4 hr). In pigeons, LY233053 potently antagonized (ED50 = 1.3 mg/kg i.m.) the behavioral suppressant effects of 10 mg/kg of NMDA. However, a dose of 160 mg/kg, i.m., was required to produce phencyclidine-like catalepsy in pigeons. In mice, LY233053 protected against maximal electroshock-induced seizures at lower doses (ED50 = 19.9 mg/kg i.p.) than those that impaired horizontal screen performance (ED50 = 40.9 mg/kg i.p.). Cholinergic and GABAergic neuronal degenerations after striatal infusion of NMDA were prevented by single or multiple i.p. doses of LY233053. In summary, the antagonist activity of LY233053 after systemic administration demonstrates potential therapeutic value in conditions of neuronal cell loss due to NMDA receptor excitotoxicity.

Schoepp, D.D.; Ornstein, P.L.; Leander, J.D.; Lodge, D.; Salhoff, C.R.; Zeman, S.; Zimmerman, D.M. (Eli Lilly and Company, Indianapolis, IN (USA))

1990-12-01T23:59:59.000Z

446

Correlation of hetorogeneous blood flow and uptake of a di-methyl-branched IODO fatty acid in the normal and ischemic dog heart  

SciTech Connect (OSTI)

Myocardial blood flow (MBF) is heterogeneously distributed in normal and ischemic myocardium (myoc). Methylated iodinated fatty acids, like 15-(p-I-125-iodophenyl)-3,3-dimethylpentadecanoic acid (DMIPPA) can be used to study fatty acid metabolism with SPECT. We studied the relationship between DMIPPA uptake and MBF. In 10 open-chest dogs, ischemica was induced in the LAD coronary artery by an extra-corporal bypass system. MBF was measured with Sc-46 labeled microspheres. Fourty min. after DMIPPA iv. (34{plus_minus}4 MBq), hearts were excised and left ventricles were cut into 120 pieces, weighed and radioactivities counted. MBF and DMIPPA uptake were determined by counting in normal and ischemic myoc. Heterogeneity is expressed as the coefficient of variation (CV) and agreement as the CV of the DMIPPA uptake to MBF ratio. A control study, normal flow in LAD, in 4 dogs revealed no differences in MBF or DMIPPA uptake between the cannulated versus native perfused myoc. We conclude the DMIPPA detects ischemia, in which it shows a different relation with MBF compared to normal myoc. DMIPPA is less heterogeneously distributed than MBF and agreement between MFB and DMIPPA uptake decreases during ischemia.

Sloof, G.W.; Visser, F.C.; Comans, E.F.I. [Free Univ. Hospital, Amsterdam (Netherlands)]|[Oak Ridge National Lab., TN (United States)] [and others

1995-05-01T23:59:59.000Z

447

Scanning tunneling microscopy of dimeric and polymeric products of electroreduced (Re(CO) sub 3 (4-vinyl,4 prime -methyl-2,2 prime -bipyridine)Cl)  

SciTech Connect (OSTI)

Scanning tunneling microscopy (STM) was used to image adsorbed products resulting from electroreduction of (Re(CO){sub 3}(vbpy)Cl) (vbpy = 4-vinyl,4{prime}-methyl-2,2{prime}-bipyridine) on highly oriented pyrolytic graphite (HOPG). STM images, in air, of HOPG electrodes following electroreduction of (Re(CO){sub 3}(vbpy)Cl) (in acetonitrile/0.1 M tetra-n-butylammonium perchlorate) by cycling the potential between 0 and {minus}2.0 V vs a sodium saturated colomel electrode (SSCE) show molecular species uniformly distributed on the surface including approximately dumbbell shaped molecules ({approx} 40 {times} 20 {angstrom}). The size and shape of these aggregates is consistent with products derived from vinyl-vinvyl coupling of Re-Re bonded dimers: ((vbpy)(CO){sub 3}Re-Re(CO){sub 3}(vbpyH-vbpyH)(CO){sub 3}Re-Re(CO){sub 3}(vbpy)). STM images of electrodes prepared by cycling the potential between 0 and {minus}1.45 V vs SSCE (less reducing conditions) show highly nonuniform coating of the surface by polymer. Several polymer morphologies were observed with polymer nucleation preferentially occurring at step sites on HOPG.

Snyder, S.R.; White, H.S. (Univ. of Minnesota, Minneapolis (USA)); Lopez, S.; Abruna, H.D. (Cornell Univ., Ithaca, NY (USA))

1990-02-14T23:59:59.000Z

448

Rotational spectroscopy as a tool to investigate interactions between vibrational polyads in symmetric top molecules: low-lying states v8 <= 2 of methyl cyanide, CH$_3$CN  

E-Print Network [OSTI]

Spectra of methyl cyanide were recorded to analyze interactions in low-lying vibrational states and to construct line lists for radio astronomical observations as well as for infrared spectroscopic investigations of planetary atmospheres. The rotational spectra cover large portions of the 36-1627 GHz region. In the infrared (IR), a spectrum was recorded for this study in the region of 2nu8 around 717 cm-1 with assignments covering 684-765 cm-1. Additional spectra in the nu8 region were used to validate the analysis. The large amount and the high accuracy of the rotational data extend to much higher J and K quantum numbers and allowed us to investigate for the first time in depth local interactions between these states which occur at high K values. In particular, we have detected several interactions between v8 = 1 and 2. Notably, there is a strong Delta(v8) = +- 1, Delta(K) = 0, Delta(l) = +-3 Fermi resonance between v8 = 1^-1 and v8 = 2^+2 at K = 14. Pronounced effects in the spectrum are also caused by reso...

Müller, Holger S P; Drouin, Brian J; Pearson, John C; Kleiner, Isabelle; Sams, Robert L; Sung, Keeyoon; Ordu, Matthias H; Lewen, Frank

2015-01-01T23:59:59.000Z

449

Alpha and recoil track detection in poly(methyl methacrylate) (PMMA)—Towards a method for in vitro assessment of radiopharmaceuticals internalized in cancer cells  

SciTech Connect (OSTI)

A method for detection and characterization of single MeV ?-particle and recoil tracks in PMMA photoresist by atomic force microscopy (AFM) analysis has been demonstrated. The energy deposition along the track is shown to lead to a latent pattern in the resist due to contrast reversal. It has been shown that the pattern, consisting of conical spikes, can be developed by conventional processing as a result of the dissolution rate of poly(methyl methacrylate) (PMMA) being greater than that for the modified material in the cylindrical volume of the track core. The spikes can be imaged and counted by routine AFM analysis. Investigations by angular-resolved near-grazing incidence reveal additional tracks that correspond to recoil tracks. The observations have been correlated with modelling, and shown to be in qualitative agreement with prevailing descriptions of collision cascades. The results may be relevant to technologies that are based on detection and characterization of single energetic ions. In particular, the direct visualization of the collision cascade may allow more accurate estimates of the actual interaction volume, which in turn will permit more precise assessment of dose distribution of ?-emitting radionuclides used for targeted radiotherapy. The results could also be relevant to other diagnostic or process technologies based on interaction of energetic ions with matter.

Myhra, S., E-mail: sverre.myhra@materials.ox.ac.uk; Chakalova, R. [Oxford University Begbroke Science Park, University of Oxford, Oxford (United Kingdom)] [Oxford University Begbroke Science Park, University of Oxford, Oxford (United Kingdom); Falzone, N. [MRC/CRUK Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, United Kingdom and Department of Biomedical Science, Tshwane University of Technology, Pretoria (South Africa)] [MRC/CRUK Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, United Kingdom and Department of Biomedical Science, Tshwane University of Technology, Pretoria (South Africa)

2014-03-15T23:59:59.000Z

450

Pump-beam-induced optical damage depended on repetition frequency and pulse width in 4-dimethylamino-N Prime -methyl-4 Prime -stilbazolium tosylate crystal  

SciTech Connect (OSTI)

We investigated the dependence of optical damage to an organic nonlinear optical crystal of 4-dimethylamino-N Prime -methyl-4 Prime -stilbazolium tosylate (DAST) on the repetition frequency and pulse width of the pump beam used to cause the thermal damage. For a pump beam with a pulse width of 15 ns at a wavelength of 1064 nm, the highest damage threshold of 8.0 J/cm{sup 2} was measured for repetition frequencies in the range from 10 to 40 Hz. On the other hand, DAST crystals were easily damaged under the repetition rates from 50 to 100 Hz. For 600-ps pulses, a higher damage threshold that was a factor of 11 to 28 times higher in terms of peak intensity was obtained compared with that of 15-ns pulses. In both the cases of 15-ns pulse duration and 600-ps duration, we demonstrated that the thermal effects in DAST crystals dominated the optical damage, which depended on thermal accumulation and dissipation.

Matsukawa, Takeshi; Nawata, Kouji; Notake, Takashi; Qi Feng; Kawamata, Hiroshi; Minamide, Hiroaki [Tera-photonics Laboratory, RIKEN, 519-1399, Aramaki-Aoba, Aoba-ku, Sendai 980-0845 (Japan)

2013-07-08T23:59:59.000Z

451

Fourier transform electron paramagnetic resonance study of the photoreduction of anthraquinone with 4-methyl-2,6-di-tert-butylphenol in alcoholic solutions  

SciTech Connect (OSTI)

Using FT-EPR following laser excitation, the primary photochemical process in the photoreduction of anthraquinone with 4-methyl-2,6-di-tert-butylphenol was investigated. High-resolved spin-polarized EPR spectra taken with nanosecond time resolution gave unambiguous evidence for a two-step hydrogen abstraction reaction, consisting of a primary electron transfer followed by proton abstraction with a time delay, which allows for a noticeable escape probability of the initially generated anthrasemiquinone radical anion (AQ{sup {sm_bullet}minus}). The time dependence of the EPR intensities of the neutral 10-hydroxy-anthroxyl radical (AQH{sup {sm_bullet}}) as well as of AQ{sup {sm_bullet}} could be simulated for the full experimentally accessible time interval of 10 ns to 100 {mu}s. The kinetic model used invokes optical spin polarization, spin-lattice relaxation, radical generation, and AQH{sup {sm_bullet}}AQ interconversion. In addition, from an analysis of the highly-resolved FT-EPR spectra a complete set of AQH{sup {sm_bullet}} hyperfine splitting (hfs) constants could be measured in two different alcohols for the first time. 30 refs., 4 figs., 2 tabs.

Plueschau, M.; Kroll, G. [Universitaet Dortmund (Germany); Dinse, K.P. [TH Darmstadt (Germany)] [and others

1992-10-29T23:59:59.000Z

452

Desorption of carbon monoxide from nickel using mercaptans  

SciTech Connect (OSTI)

An IR spectroscopic study on the displacement of carbon monoxide with 1-propyl, 2-propyl-, 1-butyl-, 2-butyl-, and tert.-butyl mercaptan from nickel foil and silica-supported nickel showed that at low carbon monoxide coverage on supported nickel, mercaptan adsorption initially converted bridged to linear carbon monoxide surface species. At higher mercaptan pressures, carbon monoxide desorbed into the gas phase. A small amount of carbon monoxide remained on the surface when the poisoned sample was evacuated, and additional carbon monoxide adsorbed when 5 mm Hg of carbon monoxide was added to the evacuated sample.

Neff, L.D.; Sturdivant, A.E.; Wallace, J.L.

1980-06-01T23:59:59.000Z

453

The design of new ligands and transition metal compounds for the oxidation of organic compounds  

E-Print Network [OSTI]

dehydrated by heating under dynamic vacuum at 150?C for 3 hours. The anhydrous materials were stored in a dry box under nitrogen. (R)-binaphthol was obtained from ABCR Chemical and 3,5-di-tert-butyl salicylaldehyde was obtained from Advanced Asymmetrics.... All other reagents were used as received. All NMR chemical shifts are given in ppm and were recorded on a Mercury-300BB spectrometer ( 1 H, 299.91 MHz; 13 C { 1 H} 75.41 MHz) using the solvent as an internal standard (CDCl 3 (or residual CHCl 3...

Grill, Joseph Michael

2009-06-02T23:59:59.000Z

454

Acute effects of a sarin-like organophosphorus agent, bis(isopropyl methyl)phosphonate, on cardiovascular parameters in anaesthetized, artificially ventilated rats  

SciTech Connect (OSTI)

The organophosphorus compound sarin irreversibly inhibits acetylcholinesterase. We examined the acute cardiovascular effects of a sarin-like organophosphorus agent, bis(isopropyl methyl)phosphonate (BIMP), in anaesthetized, artificially ventilated rats. Intravenous administration of BIMP (0.8 mg/kg; the LD50 value) induced a long-lasting increase in blood pressure and tended to increase heart rate. In rats pretreated with the non-selective muscarinic-receptor antagonist atropine, BIMP significantly increased both heart rate and blood pressure. In atropine-treated rats, hexamethonium (antagonist of ganglionic nicotinic receptors) greatly attenuated the BIMP-induced increase in blood pressure without changing the BIMP-induced increase in heart rate. In rats treated with atropine plus hexamethonium, intravenous phentolamine (non-selective ?-adrenergic receptor antagonist) plus propranolol (non-selective ?-adrenergic receptor antagonist) completely blocked the BIMP-induced increases in blood pressure and heart rate. In atropine-treated rats, the reversible acetylcholinesterase inhibitor neostigmine (1 mg/kg) induced a transient increase in blood pressure, but had no effect on heart rate. These results suggest that in anaesthetized rats, BIMP induces powerful stimulation of sympathetic as well as parasympathetic nerves and thereby modulates heart rate and blood pressure. They may also indicate that an action independent of acetylcholinesterase inhibition contributes to the acute cardiovascular responses induced by BIMP. - Highlights: • A sarin-like agent BIMP markedly increased blood pressure in anaesthetized rats. • Muscarinic receptor blockade enhanced the BIMP-induced increase in blood pressure. • Ganglionic nicotinic receptor blockade attenuated the BIMP-induced response. • Blockade of ?- as well as ?-receptors attenuated the BIMP-induced response.

Watanabe, Yoshimasa [Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Itoh, Takeo, E-mail: titoh@med.nagoya-cu.ac.jp [Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Shiraishi, Hiroaki [Department of Forensic Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Maeno, Yoshitaka [Department of Forensic Medical Science, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Arima, Yosuke; Torikoshi, Aiko; Namera, Akira [Department of Forensic Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Makita, Ryosuke [Department of Nursing, Faculty of Health Sciences, Hiroshima Cosmopolitan University, Hiroshima (Japan); Yoshizumi, Masao [Department of Cardiovascular Physiology and Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan); Nagao, Masataka [Department of Forensic Medicine, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima (Japan)

2013-10-01T23:59:59.000Z

455

Electrochemistry and photocurrents of the tris(bipyridine)ruthenium(II) and methyl viologen cations immobilized in carrageenan hydrogel. [tris(2,2'-bipyridine)ruthenium(II)  

SciTech Connect (OSTI)

A procedure for immobilization of both a photochromophore, tris(2,2{prime}-bipyridine)ruthenium(II) (Ru(bpy){sub 3}{sup 2+}), and a quencher, methyl viologen (MV{sup 2+}), within a carrageenan hydrogel matrix at an electrode surface is described. Ru(bpy){sub 3}{sup 2+} and MV{sup 2+} exhibited diffusion coefficients that ranged from 10{sup {minus} 7} to 10{sup {minus} 6} cm{sup 2}/s in the hydrogel, which represents an improvement over other immobilization matrices. Photolysis of the resulting hydrogel surface modified electrodes gave rise to a significant photocurrent which depended on the concentrations of Ru(bpy){sub 3}{sup 2+}, MV{sup 2+}, and triethanolamine and resulted in a maximum value of 12 {mu}A/cm{sup 2} after the hydrogel was cured with a solution containing 5 mM Ru(bpy){sub 3}{sup 2+} and 50 mM MV{sup 2+}. The photocurrent was the result of reoxidation of MV{sup +} at the electrode surface following reduction of MV{sup 2+} by photoexcited Ru(bpy){sub 3}{sup 2+}. The quenching rate constant of Ru(bpy){sub 3}{sup 2+} by MV{sup 2+} in the hydrogel was 4.2 {times} 10{sup 8} M{sup {minus}1} s{sup {minus}1}. The photocurrent action spectrum was consistent with Ru(bpy){sub 3}{sup 2+} acting as the photochromophore. Offsetting the potential of the hydrogel electrode verified the role of the MV{sup 2+}/{sup +} redox couple as the source of the current.

Rillema, D.P.; Edwards, A.K. (Univ., of North Carolina, Charlotte (United States)); Perine, S.C.; Crumbliss, A.L. (Duke Univ., Durham, NC (United States))

1991-11-13T23:59:59.000Z

456

Photochemical generation of alkyl radicals and their reactions with methyl viologen radical cation and with transition-metal complexes in aqueous solution  

SciTech Connect (OSTI)

The irradiation of aqueous solutions of RCo((14)aneN{sub 4})(H{sub 2}O){sup 2+} (R = CH{sub 3}, C{sub 2}H{sub 5}, 1-C{sub 3}H{sub 7}, CH{sub 2}Cl, CH{sub 2}Br, CH{sub 2}OCH{sub 3}) with visible light, {lambda} {le} 400 nm, results in the homolysis of the cobalt-carbon bond. These complexes are quite unreactive toward a variety of dealkylating and redox reagents and thus represent a convenient source of small unstabilized carbon-centered radicals in the presence of potential substrates. The radicals react rapidly with the methyl viologen radical cation, k{sub MB} = (1-2) {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}. The kinetics of the formation of RCr{sup 2+} and RCo((14)aneN{sub 4})(H{sub 2}O){sup 2+} in the reactions of radicals with Cr{sup 2+} and Co((14)aneN{sub 4})(H{sub 2}O){sub 2}{sup 2+}, respectively, were studied by using MV{sup +} as a probe. The respective rate constants have values k{sub Cr} = (1.9-2.4) {times} 10{sup 8} M{sup {minus}1} s{sup {minus}1} and k{sub Co} = (1