Novel organic-vycor glass composite membrane having Si-C bonds

A novel organic-ceramic membrane having stable Si-C bonds was developed for separation of high temperature organic solutions. Porous vycor glass was employed for a substrate which was modified by a series of chemical vapor deposition (CVD) and hydrosilylation. 1,3,5,7-Tetramethylcyclotetrasiloxane (H4) was used as a CVD source in order to introduce Si-H bonds on the surface of porous vycor glass. The Si-H bonds were then catalytically hydrosilylated with olefins. As a result, organic functional groups were introduced via Si-C bonds. A compact membrane was obtained when CVD treatment was carried out at 343 K. The membrane that was modified by the hydrosilylation of styrene showed benzene permselectiviy in benzene/cyclohexane vapor permeation test at 373 K. The separation factor of benzene over cyclohexane was 2.9 and benzene flux was 1.2 × 10 ^-5 mol m ^-2s ^-1Pa ^-1, and the permeation properties are stable for more than 1000 min at 373 K.