Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
MECHANISTIC STUDIES OF THE SIDE-CHAIN ALKYLATION OF TOLUENE WITH METHANOL ON BASIC ZEOLITES-Y BY MULTINUCLEAR NMR-SPECTROSCOPY
Autore:
HUNGER M; SCHENK U; WEITKAMP J;
Indirizzi:
UNIV STUTTGART,INST CHEM TECHNOL 1 D-70550 LEIPZIG GERMANY
Titolo Testata:
Journal of molecular catalysis. A, Chemical
fascicolo: 1-3, volume: 134, anno: 1998,
pagine: 97 - 109
SICI:
1381-1169(1998)134:1-3<97:MSOTSA>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
SOLID-STATE NMR; ALKALI-MODIFIED ZEOLITES; MAGIC-ANGLE; MAS NMR; METHOXY GROUPS; METHYL-IODIDE; CESIUM; CATALYSIS; CS-133; CATIONS;
Keywords:
SIDE-CHAIN ALKYLATION OF TOLUENE; BASIC ZEOLITES; CESIUM CATIONS; SOLID-STATE NMR SPECTROSCOPY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
29
Recensione:
Indirizzi per estratti:
Citazione:
M. Hunger et al., "MECHANISTIC STUDIES OF THE SIDE-CHAIN ALKYLATION OF TOLUENE WITH METHANOL ON BASIC ZEOLITES-Y BY MULTINUCLEAR NMR-SPECTROSCOPY", Journal of molecular catalysis. A, Chemical, 134(1-3), 1998, pp. 97-109

Abstract

The side-chain alkylation of toluene with methanol on cesium-exchanged zeolites Y, with and without subsequent impregnation with cesium hydroxide, was investigated by Cs-133 and C-13 MAS NMR spectroscopy. In the first step, the catalysts under study were characterized by different spectroscopic techniques showing a high dispersion of the oxidic guest compound on the zeolitic host and an influence of the guest compound on the intrinsic base strength of the host framework. Adsorption oftoluene led to Cs-133 MAS NMR signals pointing to a strong interaction of the toluene molecules with the cesium cations. C-13 MAS NMR experiments on the zeolites Y loaded with pure methanol and toluene/methanol mixtures revealed a rapid decomposition of formaldehyde formed by dehydrogenation of methanol. Interestingly, on the impregnated zeolite Y, formaldehyde decomposition was inhibited by toluene. Parallel to theconversion of methanol to formaldehyde, surface-bound formate specieswere formed. Since these species were stable at high reaction temperatures, as well, they may be responsible for catalyst deactivation. (C)1998 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 10:40:12