HYDROLYTICALLY STABLE BONDED CHROMATOGRAPHIC PHASES PREPARED THROUGH HYDROSILATION OF OLEFINS ON A HYDRIDE-MODIFIED SILICA INTERMEDIATE

A novel method for the preparation of bonded stationary phases is described in which a hydrocarbonaceous moiety is bound to silica surfaces through a direct silicon-carbon linkage. An established method involving the chlorination and reduction of silica was used to prepare an intermediate material containing fairly stable silicon hydride species. In the present report, such an intermediate was reacted with terminal vinyl organic functionalities in the presence of a platinum catalyst. IR and NMR spectroscopic evidence confirmed the attachment of hydrocarbonaceous ligands onto the silica surface. Typical alkyl surface densities were 4.4 and 2.5-mu-mol/m2 for octyl and octadecyl groups, respectively. The extent of coverage was found to be strongly dependent on olefin concentration and reaction temperature. When compared to the corresponding organosilanization product, the bonded silica was shown to have improved hydrolytic stability toward aqueous solutions containing trifluoroacetic acid.