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Published November 1993 | public
Journal Article

Kinetic Study of the Reactions of Chlorosilanes with Porous Vycor Glass

Abstract

The alternating reactions of SiCl_4 and H_2O with the surface of Vycor glass have been studied by thermogravimetric analysis at 400-600°C. The results are interpreted by postulating two types of silanol groups (Si-OH) on the Vycor surface, paired and isolated. Reaction of SiCl_4 with paired silanols proceeds by competing steps which control the total extent of silylation. Upon reaction with H_2O, all surface Si-Cl groups are hydrolyzed, reproducing Si-OH. Simultaneous silanol-silanol and silanol-surface chloride condensations eliminate H_2O or HCl to form new Si-O-Si bridges with final product silica. A kinetic model incorporating the silylation, hydrolysis, and condensation steps describes well the TGA data.

Additional Information

© 1993 Academic Press. Received Mach 15, 1993; accepted June 22, 1993. The authors appreciate the funding of this work by the Department of Energy under the University Coal Research Program, Grant DE-FG22-92PC92525.

Additional details

Created:
August 20, 2023
Modified:
October 24, 2023