Surface properties of fumed silica (Cab-O-Sil) and Cab-O-Sil-supported Pt and Cu catalysts, studied by ir spectroscopy

Kiss T., János and Pálinkó, István and Molnár, Árpád (1993) Surface properties of fumed silica (Cab-O-Sil) and Cab-O-Sil-supported Pt and Cu catalysts, studied by ir spectroscopy. JOURNAL OF MOLECULAR STRUCTURE, 293 (C). pp. 273-278. ISSN 0022-2860

Text 1143660.pdf Restricted to Registered users only Download (595kB) | Request a copy

Abstract

Results of ir investigations are reponed on some surface properties of a fumed silica (Cab-O-Sil) support, a Pt catalyst made by impregnation (Pt/CS-1) and two Cu catalysts made by precipitation (Cu/CS-P) or ion-exchange (Cu/CS-X). The support and the catalysts were studied in the OH-OD exchange reaction of surface OH groups by consecutive treatment with H-2 and D2 or H-2 and D2O. The behaviour of the Cu and Pt catalysts was investigated in the isomerization of methylenecyclohexane. The effects of 1,1-dimethylcyclopropane on the catalysts and the support in the presence or absence of D2 were also examined. The major findings were as follows: (i) OH-OD exchange with D2 is negligible for the support at room temperature, but the reaction is practically complete at 673 K, (ii) exchange is fast over Pt/CS-1, even at room temperature, but both Cu/CS catalysts are considerably less active, (iii) at ambient temperature, exchange with D2O proceeds almost to completion over the support and over each catalyst, (iv) isomerization of methylenecyclohexane occurs over Pt/CS-1, but not over the copper catalysts, (v) 1, 1-dimethylcyclopropane adsorbs dissociatively over each catalyst without D2, (vi) in the presence of D2, however, it reacts through associatively adsorbed species over the copper catalysts, while a dissociative mechanism is observed together with the predominant associative ring opening over Pt/CS-1.

Actions (login required)

Edit Item