skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Measurements and modeling of DO{sub 2} formation in the reactions of C{sub 2}D{sub 5} and C{sub 3}D{sub 7} radicals with O{sub 2}.

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
914888
Report Number(s):
ANL/CHM/JA-58035
Journal ID: ISSN 1089-5639; JPCAFH; TRN: US200812%%132
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Phys. Chem. A; Journal Volume: 111; Journal Issue: 19 ; May 17, 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; HYDROPEROXY RADICALS; ETHYL RADICALS; PROPYL RADICALS; DEUTERIUM COMPOUNDS; CHEMICAL REACTION KINETICS; OXIDATION; MATHEMATICAL MODELS

Citation Formats

Estupinan, E. G., Smith, J. D., Tezaki, A., Taatjes, C. A., Klippenstein, S. J., Chemistry, and SNL. Measurements and modeling of DO{sub 2} formation in the reactions of C{sub 2}D{sub 5} and C{sub 3}D{sub 7} radicals with O{sub 2}.. United States: N. p., 2007. Web. doi:10.1021/jp067602a.
Estupinan, E. G., Smith, J. D., Tezaki, A., Taatjes, C. A., Klippenstein, S. J., Chemistry, & SNL. Measurements and modeling of DO{sub 2} formation in the reactions of C{sub 2}D{sub 5} and C{sub 3}D{sub 7} radicals with O{sub 2}.. United States. doi:10.1021/jp067602a.
Estupinan, E. G., Smith, J. D., Tezaki, A., Taatjes, C. A., Klippenstein, S. J., Chemistry, and SNL. Thu . "Measurements and modeling of DO{sub 2} formation in the reactions of C{sub 2}D{sub 5} and C{sub 3}D{sub 7} radicals with O{sub 2}.". United States. doi:10.1021/jp067602a.
@article{osti_914888,
title = {Measurements and modeling of DO{sub 2} formation in the reactions of C{sub 2}D{sub 5} and C{sub 3}D{sub 7} radicals with O{sub 2}.},
author = {Estupinan, E. G. and Smith, J. D. and Tezaki, A. and Taatjes, C. A. and Klippenstein, S. J. and Chemistry and SNL},
abstractNote = {No abstract prepared.},
doi = {10.1021/jp067602a},
journal = {J. Phys. Chem. A},
number = 19 ; May 17, 2007,
volume = 111,
place = {United States},
year = {Thu May 17 00:00:00 EDT 2007},
month = {Thu May 17 00:00:00 EDT 2007}
}
  • The kinetics of the reactions of CH{sub 3}, C{sub 2}H{sub 5}, i-C{sub 3}H{sub 7}, s-C{sub 4}H{sub 9}, and t-C{sub 4}H{sub 9} with HI were studied in a tubular reactor coupled to a photoionization mass spectrometer. Rate constants were measured as a function of temperature (typically between 295 and 648 K) to determine Arrhenius parameters. These results were combined with determinations of the rate constants of the reverse reactions (I + hydrocarbon) determined previously by others to obtain equilibrium constants for the following reaction: R + HI {leftrightarrow} R-H + I. Second and Third Law based analyses using these equilibrium constantsmore » yielded heats of formation for the five alkyl radicals whose R + HI reactions were studied. The Third Law heats of formation (obtained using calculated entropies) are extremely accurate, within {plus minus} 2 kJ mol{sup {minus}1} of the current best values. The cause of the long-standing disparity that has existed between the heats of formation of the alkyl radicals derived from studies of R + HI {leftrightarrow} R-H + I equilibria and those obtained from investigation of dissociation-recombination equilibria has been identified. It is the difference between the assumed generic activation energy of R + HI rate constants (4 kJ mol{sup {minus}1}) that had been used in all prior thermochemical calculations and the actual values of these activation energies. A complex mechanism for R + HI reactions that is consistent with the observed kinetic behavior of these reactions is discussed.« less
  • The macrocyclic alkylnickel(II) complexes, RNi(tmc)/sup +/ (R = C/sub 2/H/sub 5/, C/sub 3/H/sub 7/, and CH/sub 2/-c-C/sub 5/H/sub 9/; tmc = (1R,4R,8S,11S)-1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), react with alkyl halides R'X (R' = CH/sub 3/, C/sub 2/H/sub 5/, 1-C/sub 3/H/sub 7/, 2-C/sub 3/H/sub 7/, and PhCH/sub 2/) in alkaline aqueous solutions, yielding combination and disproportionation products of R and R'. The reactivity of R'X increases in the order methyl < primary < secondary and Cl < Br < I. In the case R = R' = C/sub 2/H/sub 5/, the product distribution compares with that determined independently for ethyl radicals in aqueous solution. Themore » proposed one-electron reduction of alkyl halide by the alkylnickel complexes in the rate-determining step produces an organonickel(III) complex and the alkyl halide radical anion. Both products rapidly eliminate ethyl radicals whose self-reactions yield the final products. Alkyl halide/alkyl radical exchange reactions effectively compete with radical self-reactions. The rate constant for the reaction C/sub 2/H/sub 5/ + 2-C/sub 3/H/sub 7/I ..-->.. 2-C/sub 3/H/sub 7/ + C/sub 2/H/sub 5/I in aqueous solution was determined by competition with V(H/sub 2/O)/sub 6//sup 2 +/. The value k/sub 2-PrI/ approx. 6 x 10/sup 5/ M/sup -1/ s/sup -1/ is significantly higher than in aprotic solvents. 50 references, 2 figures, 3 tables.« less
  • Alkoxy radicals are important species in the atmospheric degradation of hydrocarbons as well as in combustion processes. Additionally, they play a crucial role in the pyrolysis of oxygen-containing hydrocarbons. The reactions of C{sub 2}H{sub 5} with O, O{sub 3}, and NO{sub 3} have been investigated in a discharge flow reactor at room temperature and pressures between 1 and 3 mbar. The reaction products were detected by mass spectrometry with electron-impact ionization. The product pattern observed is explained in terms of the decomposition of an intermediately formed, chemically activated ethoxy radical. It is shown that, with this assumption, the experimentally determinedmore » branching ratios of the different product channels can be reproduced nearly quantitatively by RRKM calculations based on ab initio results for the stationary points of the potential energy surface of C{sub 2}H{sub 5}O. For C{sub 2}H{sub 5} + O and C{sub 2}H{sub 5} + O{sub 3}, the existence of an additional, parallel channel leading to OH has to be assumed.. High-pressure Arrhenius parameters for the unimolecular reactions of the ethoxy radical are given and discussed.« less
  • The bimolecular rate constant for the title reaction has been measured with the very low pressure reactor technique (VLPR) at 295 K. The rate constant at room temperature (295 K) was found to be k/sub 1/ = (8.30 /plus minus/ 0.7) /times/ 10/sup /minus/12/ cm/sup 3//(molecule/center dot/s). The value of K/sub 1/, i.e., equilibrium constant at room temperature, was found to be (4.70 /plus minus/ 0.3) /times/ 10/sup 2/. From third law calculations at 295 K /delta/H/sub f//degree/(C/sub 2/D/sub 5/) = (24.30 /plus minus/ 0.4) kcal/mol and DH/degree/(C/sub 2/D/sub 5/-D) = 102.8 /plus minus/ 0.4 kcal/mol. With use of knownmore » zero-point energy differences DH/degree/(C/sub 2/H/sub 5/-H) can be calculated from this as 100.4 kcal/mol and /delta/H/sub f//degree/(C/sub 2/H/sub 5/) = 28.3 kcal/mol in excellent agreement with recent data. 22 references, 4 figures, 3 tables.« less
  • A novel technique using a flowing afterglow-Langmuir probe apparatus for measurement of temperature dependences of rate constants for dissociative recombination (DR) is presented. Low ({approx}10{sup 11} cm{sup -3}) concentrations of a neutral precursor are added to a noble gas/electron afterglow plasma thermalized at 300-500 K. Charge exchange yields one or many cation species, each of which may undergo DR. Relative ion concentrations are monitored at a fixed reaction time while the initial plasma density is varied between 10{sup 9} and 10{sup 10} cm{sup -3}. Modeling of the decrease in concentration of each cation relative to the non-recombining noble gas cationmore » yields the rate constant for DR. The technique is applied to several species (O{sub 2}{sup +}, CO{sub 2}{sup +}, CF{sub 3}{sup +}, N{sub 2}O{sup +}) with previously determined 300 K values, showing excellent agreement. The measurements of those species are extended to 500 K, with good agreement to literature values where they exist. Measurements are also made for a range of C{sub n}H{sub m}{sup +} (C{sub 7}H{sub 7}{sup +}, C{sub 7}H{sub 8}{sup +}, C{sub 5}H{sub 6}{sup +}, C{sub 4}H{sub 4}{sup +}, C{sub 6}H{sub 5}{sup +}, C{sub 3}H{sub 3}{sup +}, and C{sub 6}H{sub 6}{sup +}) derived from benzene and toluene neutral precursors. C{sub n}H{sub m}{sup +} DR rate constants vary from 8-12 Multiplication-Sign 10{sup -7} cm{sup 3} s{sup -1} at 300 K with temperature dependences of approximately T{sup -0.7}. Where prior measurements exist these results are in agreement, with the exception of C{sub 3}H{sub 3}{sup +} where the present results disagree with a previously reported flat temperature dependence.« less