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Titolo:
Characterization of basic guest compounds on solid catalysts by C-13 CP/MAS NMR spectroscopy of surface methoxy groups
Autore:
Schenk, U; Hunger, M; Weitkamp, J;
Indirizzi:
Univ Stuttgart, Inst Chem Technol 1, D-70550 Stuttgart, Germany Univ Stuttgart Stuttgart Germany D-70550 l 1, D-70550 Stuttgart, Germany
Titolo Testata:
MAGNETIC RESONANCE IN CHEMISTRY
, volume: 37, anno: 1999,
pagine: S75 - S78
SICI:
0749-1581(199912)37:<S75:COBGCO>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
CATION-EXCHANGED ZEOLITES; ALKALI-MODIFIED ZEOLITES; METHYL-IODIDE; METHANOL; ALKYLATION; FRAMEWORK; TOLUENE; FAUJASITE; OXIDES; SITE;
Keywords:
NMR; C-13 CP/MAS NMR; surface methoxy groups; basic catalysts; guest compounds;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
26
Recensione:
Indirizzi per estratti:
Indirizzo: Hunger, M Univ Stuttgart, Inst Chem Technol 1, D-70550 Stuttgart, Germany Univ Stuttgart Stuttgart Germany D-70550 50 Stuttgart, Germany
Citazione:
U. Schenk et al., "Characterization of basic guest compounds on solid catalysts by C-13 CP/MAS NMR spectroscopy of surface methoxy groups", MAGN RES CH, 37, 1999, pp. S75-S78

Abstract

Silica gel, dealuminated zeolite USY and cesium-exchanged zeolite Y were impregnated with alkali metal hydroxides or acetates followed by calcination. Surface methoxy groups formed upon loading these samples with methyl iodide were applied as C-13 NMR spectroscopic probes to investigate the formation of well dispersed basic guest compounds. The variation of the isotropic C-13 NMR shifts of methoxy groups bound to different guest compounds on silica gel (49.6-48.7 ppm) shows the same tendency as the electronegativities of alkali metal atoms introduced by impregnation. C-13 CP/MAS NMR studies of surface methoxy groups bound to guest compounds on silica gel and zeolites Y revealed an influence of the support on the C-13 chemical shift tensor. The application of this NMR spectroscopic method on cesium-exchanged zeolite Y impregnated with cesium hydroxide allows one to distinguish at least two types of oxidic guest compounds. Copyright (C) 1999 John Wiley & Sons, Ltd.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 10:38:12