ENHANCED RESOLUTION IN THE H-1-NMR SPECTRA OF ZEOLITE H-ZSM-5 BY HETERONUCLEAR DIPOLAR-DEPHASING SPIN-ECHO MAS

Authors
Citation
D. Freude, ENHANCED RESOLUTION IN THE H-1-NMR SPECTRA OF ZEOLITE H-ZSM-5 BY HETERONUCLEAR DIPOLAR-DEPHASING SPIN-ECHO MAS, Chemical physics letters, 235(1-2), 1995, pp. 69-75
Citations number
22
Categorie Soggetti
Physics, Atomic, Molecular & Chemical
Journal title
ISSN journal
00092614
Volume
235
Issue
1-2
Year of publication
1995
Pages
69 - 75
Database
ISI
SICI code
0009-2614(1995)235:1-2<69:ERITHS>2.0.ZU;2-A
Abstract
Dipolar-dephasing with high power Al-27 irradiation yields H-1 MAS NMR echo spectra of 'aluminium-unconnected' hydroxyl groups in dehydrated zeolites. The aluminium-connected SiOHal and AlOH hydroxyls can be ob served as the difference spectra. The technique increases the number o f OH lines in the 1H NMR spectra of dehydrated zeolite H-ZSM-5. Two ki nds of Bronsted sites can be distinguished and interpreted in terms of their mobility in the vicinity of framework aluminium atoms.