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Title: Effect of group IA cations on CO hydrogenation over Ru/zeolites

Abstract

The present work was undertaken to investigate systematically the influence of Group IA neutralizing cations on CO hydrogenation over zeolite-supported ruthenium catalysts. These catalysts were prepared from NH/sub 4/Y, LiY, NaY, KY, RbY, CsY, NaX, KL, and Na-mordenite zeolites by ion-exchange with ruthenium hexammine chloride. The nature of the group IA cations was found to have little effect on chemisorptive properties and on the activity and chain growth probability in CO hydrogenation on RU. However, it was established that secondary acid-catalyzed reactions of the primary olefinic products from CO hydrogenation can play a major role in shaping product selectivity. Using model reactions such as olefin transformations on the zeolites without the metal, it was established that the strength of the acid sites is a strong function of the nature of the neutralizing alkali cations remaining in the zeolite. Acid site strength was found to decrease with molecular weight of the alkali cation used. This study established the bifunctional nature of the zeolite-supported F-T catalysts and its importance in CO hydrogenation. The results suggest that the catalyst selectivity can be controlled by varying the strength of the zeolite acid sites, the most important active centers for secondary reactions of the primarymore » olefinic F-T products. Depending on the concentration and the strength of the acid sites, a function of the Si/Al ratio and the nature of the residual neutralizing cations, various competitive reaction paths can be observed for the transformation of olefinic compounds. These include isomerization, oligomerization, cracking, hydrogen transfer, etc.« less

Authors:
Publication Date:
Research Org.:
Pittsburgh Univ., PA (USA)
OSTI Identifier:
6064700
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
10 SYNTHETIC FUELS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARBON MONOXIDE; HYDROGENATION; RUTHENIUM COMPOUNDS; CATALYTIC EFFECTS; ZEOLITES; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMICAL REACTIONS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; MATERIALS; MINERALS; OXIDES; OXYGEN COMPOUNDS; REFRACTORY METAL COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; 090121* - Hydrocarbon Fuels- Chemical Synthesis- (1976-1989); 400201 - Chemical & Physicochemical Properties

Citation Formats

Oukaci, R. Effect of group IA cations on CO hydrogenation over Ru/zeolites. United States: N. p., 1986. Web.
Oukaci, R. Effect of group IA cations on CO hydrogenation over Ru/zeolites. United States.
Oukaci, R. 1986. "Effect of group IA cations on CO hydrogenation over Ru/zeolites". United States.
@article{osti_6064700,
title = {Effect of group IA cations on CO hydrogenation over Ru/zeolites},
author = {Oukaci, R},
abstractNote = {The present work was undertaken to investigate systematically the influence of Group IA neutralizing cations on CO hydrogenation over zeolite-supported ruthenium catalysts. These catalysts were prepared from NH/sub 4/Y, LiY, NaY, KY, RbY, CsY, NaX, KL, and Na-mordenite zeolites by ion-exchange with ruthenium hexammine chloride. The nature of the group IA cations was found to have little effect on chemisorptive properties and on the activity and chain growth probability in CO hydrogenation on RU. However, it was established that secondary acid-catalyzed reactions of the primary olefinic products from CO hydrogenation can play a major role in shaping product selectivity. Using model reactions such as olefin transformations on the zeolites without the metal, it was established that the strength of the acid sites is a strong function of the nature of the neutralizing alkali cations remaining in the zeolite. Acid site strength was found to decrease with molecular weight of the alkali cation used. This study established the bifunctional nature of the zeolite-supported F-T catalysts and its importance in CO hydrogenation. The results suggest that the catalyst selectivity can be controlled by varying the strength of the zeolite acid sites, the most important active centers for secondary reactions of the primary olefinic F-T products. Depending on the concentration and the strength of the acid sites, a function of the Si/Al ratio and the nature of the residual neutralizing cations, various competitive reaction paths can be observed for the transformation of olefinic compounds. These include isomerization, oligomerization, cracking, hydrogen transfer, etc.},
doi = {},
url = {https://www.osti.gov/biblio/6064700}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1986},
month = {Wed Jan 01 00:00:00 EST 1986}
}

Thesis/Dissertation:
Other availability
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