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Title: Activation of ethane on modified ZSM-5 zeolites studied under transient conditions

Abstract

The conversion of ethane on modified ZSM-5 zeolites was studied to resolve single reaction steps proceeding in the reaction network towards the formation of aromatic hydrocarbons. On zinc centers in H-ZSM-5, the straight reaction of ethane to benzene via the intermediates ethene and linear C{sub 4} olefines could be demonstrated. On Broensted acid sites, isomerization of intermediate olefines occurs leading to the formation of alkyl aromatics at longer reaction times. If ethane is pulsed under transient conditions over the evacuated catalyst bed containing H-ZSM-5 at 773 K, almost no interaction between molecule and zeolite is to observe. On the contrary, ethene is formed from ethane under the same reaction conditions if cationic zinc species are present in ZSM-5. Olefinic oligomers, being intermediates in the aromatization process, are stronger adsorbed on zinc containing than on the protonic form of ZSM-5. If the primary product ethene is pulsed over the zeolite, the activity for the formation of aromatic hydrocarbons is much higher on Zn-ZSM-5 than on H-ZSM-5. The same result is obtained if ethene is continuously fed over the catalyst at low pressure. Consequently, zinc centers play an essential role in the activation of the ethane molecule but also a major rolemore » in the further reactions to aromatic hydrocarbons.« less

Authors:
 [1];  [2];  [3]
  1. Universitaet Leipzig (Germany)
  2. Ruhr-Universitaet-Bochum (Germany)
  3. Institut fuer Technische Chemie, Bochum (Germany)
Publication Date:
OSTI Identifier:
468014
Report Number(s):
CONF-960652-
TRN: 96:004817-0051
Resource Type:
Conference
Resource Relation:
Conference: 11. international congress on catalysis (ICC-11), Baltimore, MD (United States), 30 Jun - 5 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of 11th International congress on catalysis - 40th anniversary. Part A and B; Hightower, J.W.; Delgass, W.N.; Iglesia, E.; Bell, A.T. [eds.]; PB: 1482 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ZEOLITES; CATALYTIC EFFECTS; SURFACE PROPERTIES; ZINC; ETHANE; CONVERSION; AROMATICS; AROMATIZATION; BENZENE; ISOMERIZATION; REACTION INTERMEDIATES

Citation Formats

Hagen, A, Keipert, O P, and Roessner, F. Activation of ethane on modified ZSM-5 zeolites studied under transient conditions. United States: N. p., 1996. Web.
Hagen, A, Keipert, O P, & Roessner, F. Activation of ethane on modified ZSM-5 zeolites studied under transient conditions. United States.
Hagen, A, Keipert, O P, and Roessner, F. Tue . "Activation of ethane on modified ZSM-5 zeolites studied under transient conditions". United States.
@article{osti_468014,
title = {Activation of ethane on modified ZSM-5 zeolites studied under transient conditions},
author = {Hagen, A and Keipert, O P and Roessner, F},
abstractNote = {The conversion of ethane on modified ZSM-5 zeolites was studied to resolve single reaction steps proceeding in the reaction network towards the formation of aromatic hydrocarbons. On zinc centers in H-ZSM-5, the straight reaction of ethane to benzene via the intermediates ethene and linear C{sub 4} olefines could be demonstrated. On Broensted acid sites, isomerization of intermediate olefines occurs leading to the formation of alkyl aromatics at longer reaction times. If ethane is pulsed under transient conditions over the evacuated catalyst bed containing H-ZSM-5 at 773 K, almost no interaction between molecule and zeolite is to observe. On the contrary, ethene is formed from ethane under the same reaction conditions if cationic zinc species are present in ZSM-5. Olefinic oligomers, being intermediates in the aromatization process, are stronger adsorbed on zinc containing than on the protonic form of ZSM-5. If the primary product ethene is pulsed over the zeolite, the activity for the formation of aromatic hydrocarbons is much higher on Zn-ZSM-5 than on H-ZSM-5. The same result is obtained if ethene is continuously fed over the catalyst at low pressure. Consequently, zinc centers play an essential role in the activation of the ethane molecule but also a major role in the further reactions to aromatic hydrocarbons.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1996},
month = {12}
}

Conference:
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