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
The mechanism of alkane activation over zeolite Brønsted acid sites. A density-functional study
✍ Scribed by Simon J. Collins; Patrick J. O'Malley
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 455 KB
- Volume
- 246
- Category
- Article
- ISSN
- 0009-2614
No coin nor oath required. For personal study only.
📜 SIMILAR VOLUMES
Deuteration of Bronsted acidic sites in zeolites gives observable infrared in-plane O-D bending modes. For zeolite Y and ZK-5, a maximum near 870 cm-' with a shoulder near 890 cm-' is observed. These signals arc related to, respectively, the highfrequency and the low-frequency stretching modes. Mord
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