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Title: Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports.

Abstract

A series of mesoporous synthetic organo-clay complexes has been prepared by hydrothermal crystallization of gels containing silica, magnesium hydroxide, lithium fluoride, and an organic of choice, followed by calcination to remove the organics. The organic serves to impart structural order to the inorganic network that does not disappear upon its removal. The choice of organic modifier can be used to control the pore structure of the resulting mesoporous materials. Pore size distributions appear in some cases to be related to the type of polymer packing upon clay formation in situ. These materials are being explored as Co Mo hydrodesulfurization (HDS) catalyst supports. Preliminary HDS results show performance commensurate with commercial catalysis for the mesoporous materials when a model heavy oil feed is used (1 wt% S as dibenzothiophene in hexadecane). Temperature programmed reduction experiments of used catalysts suggest a relationship between HDS activity and ease of reduction of the CoMo/clay catalysts. Reactivity of the CoMo clay also correlates with the percentage of mesopore volume remaining after reaction. Losses in mesopore volume are largely recouped by recalcination, suggesting that reversible coke is formed inside the pore structure of clays faster than inside conventional alumina.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
ER
OSTI Identifier:
937990
Report Number(s):
ANL/CHM/JA-25320
Journal ID: ISSN 1387-1811; TRN: US200906%%460
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Microporous Mesoporous Mater.; Journal Volume: 20; Journal Issue: 1998
Country of Publication:
United States
Language:
ENGLISH
Subject:
01 COAL, LIGNITE, AND PEAT; CALCINATION; CATALYSIS; CATALYST SUPPORTS; CATALYSTS; CLAYS; COKE; CRYSTALLIZATION; HEXADECANE; LITHIUM FLUORIDES; MAGNESIUM HYDROXIDES; PERFORMANCE; POLYMERS; PORE STRUCTURE; REMOVAL; SILICA

Citation Formats

Carrado, K. A., Marshall, C. L., Brenner, J. R., Song, K., and Chemistry. Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports.. United States: N. p., 1998. Web. doi:10.1016/S1387-1811(97)00017-6.
Carrado, K. A., Marshall, C. L., Brenner, J. R., Song, K., & Chemistry. Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports.. United States. doi:10.1016/S1387-1811(97)00017-6.
Carrado, K. A., Marshall, C. L., Brenner, J. R., Song, K., and Chemistry. 1998. "Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports.". United States. doi:10.1016/S1387-1811(97)00017-6.
@article{osti_937990,
title = {Materials derived from synthetic organo-clay complexes as novel hydrodesulfurization catalyst supports.},
author = {Carrado, K. A. and Marshall, C. L. and Brenner, J. R. and Song, K. and Chemistry},
abstractNote = {A series of mesoporous synthetic organo-clay complexes has been prepared by hydrothermal crystallization of gels containing silica, magnesium hydroxide, lithium fluoride, and an organic of choice, followed by calcination to remove the organics. The organic serves to impart structural order to the inorganic network that does not disappear upon its removal. The choice of organic modifier can be used to control the pore structure of the resulting mesoporous materials. Pore size distributions appear in some cases to be related to the type of polymer packing upon clay formation in situ. These materials are being explored as Co Mo hydrodesulfurization (HDS) catalyst supports. Preliminary HDS results show performance commensurate with commercial catalysis for the mesoporous materials when a model heavy oil feed is used (1 wt% S as dibenzothiophene in hexadecane). Temperature programmed reduction experiments of used catalysts suggest a relationship between HDS activity and ease of reduction of the CoMo/clay catalysts. Reactivity of the CoMo clay also correlates with the percentage of mesopore volume remaining after reaction. Losses in mesopore volume are largely recouped by recalcination, suggesting that reversible coke is formed inside the pore structure of clays faster than inside conventional alumina.},
doi = {10.1016/S1387-1811(97)00017-6},
journal = {Microporous Mesoporous Mater.},
number = 1998,
volume = 20,
place = {United States},
year = 1998,
month = 1
}
  • Various pore size distributions are found for synthetic organo-clay complexes from which the organic portion has been removed via calcination. The clays are prepared by hydrothermal crystallization of gels containing silica, magnesium hydroxide, lithium fluoride, and an organic of choice. The organic serves to impart long-range structural order to the inorganic network that does not disappear upon its removal. Mesoporous materials are prepared from a host of organic modifiers. For example, pore diameters of 40-50{Angstrom} result from tetraethyl ammonium and celluloses, and polydimethyl diallyl ammonium imparts diameters of about 110{Angstrom} on average. These materials have begun to be explored asmore » hydrodesulfurization (HDS) catalyst supports. Preliminary results show performance commensurate with commercial catalysts for the mesoporous materials when a model oil feed is used (1% dibenzothiophene in hexadecane). The target application is HDS of an actual heavy crude oil from California.« less
  • Mesoporous synthetic clays (MSCs) are obtained when polymer-containing silicate gels are hydrothermally crystallized to form layered magnesium silicate hectorite clays containing polymers that are incorporated in situ. In this in situ technique, interlayer intercalation of different polymers over broad molecular weight and concentration ranges is achieved. The polymer loading of synthesized composites is determined by thermal analysis, and the basal spacing changes resulting from different levels of polymer intercalation are monitored by X-ray powder diffraction (XRD). In some cases, intercalation occurs to such a degree as to delaminate the layers and cause loss of stacking registry. Polyvinylpyrrolidone (PVP) of severalmore » average molecular weights ranging from 10x10{sup 3}-1.3x10{sup 6}, in loadings varying from 10 to 20 wt.%, were used. The organic polymer template molecules were removed from synthetic polymer-clay complexes via calcination. Pore radii, surface areas and pore volumes of the resulting porous inorganic networks (MSCs) were then measured. A direct correlation between both PVP Mw and polymer loading on the radius of the average pore was found, which varied from 21-45 Angstroms.« less
  • Synthetic hectorites were hydrothermally crystallized with direct incorporation of a cationic polymer poly(dimethyl diallyl ammonium chloride) (PDDA), and two neutral cellulosic polymers hydroxypropyl methylcellulose (HPMC) and hydroxyethyl cellulose (HEC). Synthetic PDDA-hectorite displays the lowest d-spacing at 15.8 {Angstrom} along with less polymer incorporation (7.8 wt % organic) than the neutral polymers (18--22 wt % organic). Thermal analysis and small angle neutron scattering were used to further examine the polymer-clay systems. Clay platelets of the largest size and best stacking order occur when cationic PDDA polymer is used. PDDA also enhances these properties over the crystallites prepared for a control mineral,more » where no polymer is used. HEC acts to aggregate the silica, leaving less to react to form clay. The clay platelets which result from HEC are small, not stacked to a large degree, and oriented randomly. Neutral HPMC acts more like cationic PDDA in that larger clay platelets are allowed to form. The extended microstructure of the clay network remains undisturbed after polymer is removed by calcination. When no polymer is used, the synthetic hectorite has a N{sub 2} BET surface area of 200 M{sup 2}/gm, even after calcination. This increases by 20--50% for the synthetic polymer-hectorites after the polymer is removed by calcination.« less
  • Unsupported and silica-supported amorphous metal-boron materials (Ni-B, Mo-O-B, and Ni-Mo-O-B) were prepared by NaBH{sub 4} reduction of aqueous or impregnated metal salts. The resulting materials were characterized by a range of techniques, including conventional and time-resolved X-ray diffraction. The latter technique was used to determine the onset of crystallization of the amorphous materials during annealing in He flow and to identify the phases formed. Annealing of unsupported Ni-B resulted in the crystallization of predominantly Ni{sub 3}B, followed by Ni metal, whereas Ni-B/SiO{sub 2} formed Ni and then NiO. There was no evidence for crystallization of B-containing phases for Mo-O-B ormore » Mo-O-B/SiO{sub 2} on annealing; instead, the predominant phase formed was MoO{sub 2}. In general, the phases formed for Ni-Mo-O-B and Ni-Mo-O-B/SiO2 were consistent with those formed in the monometallic materials, but at higher annealing temperatures. Catalysts prepared by sulfiding Ni-B/SiO{sub 2} and Ni-Mo-O-B/SiO{sub 2} materials had significantly higher thiophene HDS activities than conventionally prepared sulfided Ni/SiO2 and Ni-Mo/SiO{sub 2} catalysts, whereas a sulfided Mo-O-B/SiO{sub 2} catalyst had a dramatically lower HDS activity than a sulfided Mo/SiO{sub 2} catalyst.« less