H 2'AI and %i solid-state NMR was used to determine the geometry of the Brsnsted acid site in zeolites. The mean distance between acidic protons in bridging hydroxyl groups and the nearest framework Al atom is 2.38 ? 0.04 8, in zeolite H-Y and 2.48 2 0.04 A in H-ZSM-5. The quadrupole frequency of fr
Solid-State NMR Characterization of Brønsted Acid Sites of Cesium Salt of 12-Tungstophosphoric Acid
✍ Scribed by Luzgin, Mikhail V.; Stepanov, Alexander G.
- Book ID
- 126482880
- Publisher
- American Chemical Society
- Year
- 2014
- Tongue
- English
- Weight
- 852 KB
- Volume
- 118
- Category
- Article
- ISSN
- 1932-7447
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📜 SIMILAR VOLUMES
Broad-line 'H NMR and 'H MAS NMR were used to determine the geometry of the Bransted acidic sites in zeolites H-ZSM-5. The signals obtained correspond to bridging hydroxyl groups in Si-OH-Al arrangements with an H-Al distance of 0.246-0.252 nm. The concentration of hypothetical SiOHSi groups must be
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 i