Synthesis and characterization of alkyl bonded phases from a silica hydride via hydrosilation with free radical initiation

A new approach for the hydrosilation of silica hydride surfaces by free radical addition is evaluated. The method is successful using either AIBN or tert.-butyl peroxide as the free radical initiator. A variety of organic moieties such as 1-octene, 1-triacontene, 2-methyl-3-butenitrile, 7-octene-1,2-diol, 3-butene-1-ol and propiolic acid are bonded by using at least one of the free radical species. If the organic group is small then some polymerization is observed. If a large ratio of free radical to organic compound is used then the degree of polymerization increases for the shorter chain alkyl bonded materials. A few chromatographic tests on two of the bonded phases, C-30 and 7-octene-1,2-diol, give results comparable to those obtained on identical materials made by metal complex catalysis and by conventional organosilanization. (C) 1997 Elsevier Science B.V.