F. Salehirad et Mw. Anderson, SOLID-STATE NMR-STUDIES OF ADSORPTION COMPLEXES AND SURFACE METHOXY GROUPS ON METHANOL-SORBED MICROPOROUS MATERIALS, Journal of catalysis (Print), 177(2), 1998, pp. 189-207
Multinuclear solid-state NMR has been used to study the structure of s
urface-bonded methanol structures before and after reaction on zeolite
K-ZSM-5 and zeotype H-SAPO-34. The results reveal that at low loading
s, up to one methanol per acid site, the methanol is adsorbed in two h
ydrogen bonded configurations. At higher coverages the results suggest
methanol clustering with the involvement of one methoxonium ion. Afte
r reaction at ca 500 K a variety of surface methoxy groups are observe
d on both catalysts. NMR is able to differentiate at least four methox
y groups on H-ZSM-5 and the motion of these species is discussed. (C)
1998 Academic Press.