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NMR studies of the molecular sieve VPI-5 containing only “framework” water

✍ Scribed by Heyong He; Waclaw Kolodziejski; Jacek Klinowski

Publisher
Elsevier Science
Year
1992
Tongue
English
Weight
350 KB
Volume
200
Category
Article
ISSN
0009-2614

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✦ Synopsis

The preparation of partially hydrated VPI-5, in which water molecules are strongly bonded to l/3 of framework Al atoms but there is no intracrystalline water, can be readily monitored in situ by rH NMR when fully hydrated samples are heated inside an NMR rotor. *'Al and 3'P MAS NMR spectra have also been examined. Partially and fully hydrated samples of VP19 undergo a similar symmetry change at 343-353 K, which indicates that the mobile water in the channels is not the major factor in the process.

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