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Observation of Brønsted acid sites of DY zeolite with deuterium NMR

✍ Scribed by Timothy J. Gluszak; Daniel T. Chen; Sanjay B. Sharma; James A. Dumesic; Thatcher W. Root

Publisher
Elsevier Science
Year
1992
Tongue
English
Weight
484 KB
Volume
190
Category
Article
ISSN
0009-2614

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✦ Synopsis

Solid-state deuterium NMR has been used to detect Bronsted acid sites and non-acidic silanols in D-exchanged zeohtes. The quadrupolar coupling constant for Bronsted sites in D-Y zeolite is 234 + 2 kHz, and the sites are axially symmetric. This reduction by t from the water O-D coupling constant is indicative of the acidic character ofthe O-D bond. The acid deuterons are immobile at room temperature on a millisecond timescale. Effects of reversible adsorption of ammonia are readily monitored through changes in peaks corresponding to O-D and O--NHsD+ species.

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