ISSN:
1572-879X
Keywords:
silica–alumina
;
Brønsted acidity of solids
;
1H broad-line NMR
;
1H MAS NMR
;
acidity coefficient
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract 1H broad-line (4 K) and MAS (room temperature) NMR have been used to study the acid strength of two amorphous silica–aluminas interacting or not with adsorbed water. The study is more difficult than for zeolites, because the acidic SiO(H)Al bridges are reversibly destroyed by dehydration. However, an acidity coefficient value (H3O+ concentration per Brønsted acid site when one water molecule interacts with each Brønsted site) of 0.34±10%; has been determined. This value is equal to that obtained for H-faujasite and H-mordenite samples with Si/Al ratios high enough for maximum acid strength.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1019045503800
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