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Title: Probing the basic character of alkali-modified zeolites by CO{sub 2} adsorption microcalorimetry, butene isomerization, and toluene alkylation with ethylene

Abstract

Two types of alkali-modified zeolites X and Y were studied, namely, zeolites containing occluded cesium oxides and zeolites containing occluded alkali metals (Na, Cs). Zeolites with occluded CsO{sub X}, obtained via impregnation and decomposition of cesium acetate, exhibited higher CO{sub 2} adsorption capacities and higher heats of adsorption than the corresponding ion-exchanged zeolites. However, the heats of adsorption were significantly lower on the zeolite-supported oxides ({approximately}85 kJ/mol) compared to bulk cesium oxide ({approximately}270 kJ/mol). The CO{sub 2} adsorption capacities of the zeolites containing occluded CsO{sub X} increased linearly with the amount of occluded cesium (1 CO{sub 2} per 4 occluded Cs atoms), and the catalytic activity for 1-butene isomerization was commensurate with the CO{sub 2} uptake on the materials. Stronger base sites were created in zeolites by decomposition of impregnated alkali azides (Na, Cs), due to the formation of alkali metal species. These materials were active catalysts for the side-chain alkylation of toluene with ethylene, whereas zeolites containing occluded CsO{sub X} were inactive for the reaction. Dioxygen adsorption followed by thermal treatment of zeolites containing occluded alkali metal resulted in the elimination of their activity for toluene alkylation whereas their activity for butene isomerization was retained. Alkali oxide- and alkalimore » metal-containing microporous carbon materials exhibited significantly different adsorption properties and catalytic activities from their zeolite counterparts, possibly due to the different nature of the occluded species and/or steric constraints in the amorphous carbon.« less

Authors:
;
Publication Date:
Research Org.:
Univ. of Virginia, Charlottesville, VA (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
20014522
DOE Contract Number:  
FG05-95ER14549
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 189; Journal Issue: 1; Other Information: PBD: 1 Jan 2000; Journal ID: ISSN 0021-9517
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; ZEOLITES; CESIUM OXIDES; SODIUM; CESIUM; CARBON DIOXIDE; ADSORPTION; SORPTIVE PROPERTIES; ADSORPTION HEAT; BUTENES; ISOMERIZATION; TOLUENE; ALKYLATION; CATALYTIC EFFECTS

Citation Formats

Bordawekar, S V, and Davis, R J. Probing the basic character of alkali-modified zeolites by CO{sub 2} adsorption microcalorimetry, butene isomerization, and toluene alkylation with ethylene. United States: N. p., 2000. Web. doi:10.1006/jcat.1999.2703.
Bordawekar, S V, & Davis, R J. Probing the basic character of alkali-modified zeolites by CO{sub 2} adsorption microcalorimetry, butene isomerization, and toluene alkylation with ethylene. United States. https://doi.org/10.1006/jcat.1999.2703
Bordawekar, S V, and Davis, R J. 2000. "Probing the basic character of alkali-modified zeolites by CO{sub 2} adsorption microcalorimetry, butene isomerization, and toluene alkylation with ethylene". United States. https://doi.org/10.1006/jcat.1999.2703.
@article{osti_20014522,
title = {Probing the basic character of alkali-modified zeolites by CO{sub 2} adsorption microcalorimetry, butene isomerization, and toluene alkylation with ethylene},
author = {Bordawekar, S V and Davis, R J},
abstractNote = {Two types of alkali-modified zeolites X and Y were studied, namely, zeolites containing occluded cesium oxides and zeolites containing occluded alkali metals (Na, Cs). Zeolites with occluded CsO{sub X}, obtained via impregnation and decomposition of cesium acetate, exhibited higher CO{sub 2} adsorption capacities and higher heats of adsorption than the corresponding ion-exchanged zeolites. However, the heats of adsorption were significantly lower on the zeolite-supported oxides ({approximately}85 kJ/mol) compared to bulk cesium oxide ({approximately}270 kJ/mol). The CO{sub 2} adsorption capacities of the zeolites containing occluded CsO{sub X} increased linearly with the amount of occluded cesium (1 CO{sub 2} per 4 occluded Cs atoms), and the catalytic activity for 1-butene isomerization was commensurate with the CO{sub 2} uptake on the materials. Stronger base sites were created in zeolites by decomposition of impregnated alkali azides (Na, Cs), due to the formation of alkali metal species. These materials were active catalysts for the side-chain alkylation of toluene with ethylene, whereas zeolites containing occluded CsO{sub X} were inactive for the reaction. Dioxygen adsorption followed by thermal treatment of zeolites containing occluded alkali metal resulted in the elimination of their activity for toluene alkylation whereas their activity for butene isomerization was retained. Alkali oxide- and alkali metal-containing microporous carbon materials exhibited significantly different adsorption properties and catalytic activities from their zeolite counterparts, possibly due to the different nature of the occluded species and/or steric constraints in the amorphous carbon.},
doi = {10.1006/jcat.1999.2703},
url = {https://www.osti.gov/biblio/20014522}, journal = {Journal of Catalysis},
issn = {0021-9517},
number = 1,
volume = 189,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 2000},
month = {Sat Jan 01 00:00:00 EST 2000}
}