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High-resolution solid-state nuclear magnetic resonance study of the tetrapropylammonium template in a purely siliceous MFI-type zeolite

✍ Scribed by R. Gougeon; L. Delmotte; P. Reinheimer; B. Meurer; J. M. Chézeau


Publisher
John Wiley and Sons
Year
1998
Tongue
English
Weight
256 KB
Volume
36
Category
Article
ISSN
0749-1581

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✦ Synopsis


The dynamics of tetrapropylammonium (TPA) cations occluded during the synthesis of a siliceous MFI zeolite were investigated by several 13C high-resolution NMR methods. This work follows and complements a previous 1H broad-line NMR study of this material. The evolution of the 13C cross polarization magic angle spinning (CP/MAS) spectrum of the template inside the structure was studied over a wide temperature range, from 120 to 463 K. Through the indirect measurements of 1H dipolar couplings via 13C CP/MAS NMR, it is possible to di †erentiate one of the carbons linked to nitrogen from the others, in terms of hindrance to motion. A highfrequency oscillation of the entire cation is superimposed, as shown by 13C

measurements. This study conÐrmed T 1 the great mobility of the template already observed by 1H broad-line measurements and also revealed that this mobility increases on going from the inner to the outer part of the propyl arms.