Characterization of basic sites in zeolites for toluene side-chain alkylation with methanol
Result description
Alkali metal exchanged zeolites ZSM-5, X and Y were characterized by adsorption of pyrrole and tested in toluene side-chain alkylation with methanol. Adsorption of pyrrole followed by FTIR spectroscopy and gravimetry indicated that there exist at least two different adsorption sites for pyrrole in these zeolites depending on the aluminum distribution in the framework. With increasing size of the alkali metal cation (Li < K < Cs] the possibility for adsorption of pyrrole decreases, in particular for those ZSM-5 samples with a higher nSi/nAl ratio. The highest activities in toluene side-chain alkzlation with methanol were achieved over Cs-X and Cs-Y zeolites. With Cs-ZSM-5 (nSi/nAl = 14) some methylation activity was also observed. It is proposed that not only the higher electronegativity of the zeolite catalysts but also a proper distance between two neighboring Al atoms in ZSM-5 is required for the activation of the methyl group of toluene.
Keywords
The result's identifiers
Result code in IS VaVaI
Result on the web
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DOI - Digital Object Identifier
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Alternative languages
Result language
angličtina
Original language name
Characterization of basic sites in zeolites for toluene side-chain alkylation with methanol
Original language description
Alkali metal exchanged zeolites ZSM-5, X and Y were characterized by adsorption of pyrrole and tested in toluene side-chain alkylation with methanol. Adsorption of pyrrole followed by FTIR spectroscopy and gravimetry indicated that there exist at least two different adsorption sites for pyrrole in these zeolites depending on the aluminum distribution in the framework. With increasing size of the alkali metal cation (Li < K < Cs] the possibility for adsorption of pyrrole decreases, in particular for those ZSM-5 samples with a higher nSi/nAl ratio. The highest activities in toluene side-chain alkzlation with methanol were achieved over Cs-X and Cs-Y zeolites. With Cs-ZSM-5 (nSi/nAl = 14) some methylation activity was also observed. It is proposed that not only the higher electronegativity of the zeolite catalysts but also a proper distance between two neighboring Al atoms in ZSM-5 is required for the activation of the methyl group of toluene.
Czech name
Charakterizace bazických míst v zeolitech pro alkylaci toluenu methanolem do postranního řetězce
Czech description
Zeolity ZSM-5, X a Y vyměněné alkalickými kovy byly chrakterizovány adsorpcí pyrrolu a testovány v alkylaci postranního řetězce toluenu methanolem. Adsorpce pyrrolu spolu s FTIR spektroskopií a gravimetrií ukazuje, že v těchto zeolitech existují v závislosti na distribuci Al v mřížce alespoň dvě různá místa vhodná pro adsorpci pyrrolu. S rostoucí velikostí kationtu alkalického kovu (Li
Classification
Type
D - Article in proceedings
CEP classification
CF - Physical chemistry and theoretical chemistry
OECD FORD branch
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Result continuities
Project
KJB4040402: Tailoring the zeolite properties for catalytic applications
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Z - Vyzkumny zamer (s odkazem do CEZ)
Others
Publication year
2005
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Article name in the collection
Studies in Surface Science and Catalysis
ISBN
0-444-52083-X
ISSN
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e-ISSN
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Number of pages
8
Pages from-to
1629-1636
Publisher name
Elsevier
Place of publication
Amsterdam
Event location
Prague
Event date
Aug 23, 2005
Type of event by nationality
WRD - Celosvětová akce
UT code for WoS article
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Result type
D - Article in proceedings
CEP
CF - Physical chemistry and theoretical chemistry
Year of implementation
2005