Selective Reduction of Halopolyfluorocarbons by Organosilicon Hydrides

It is demonstrated that silicon hydrides can be used for reduction of polyfluorinated halocarbons. For example, the reaction between CF(3)CCl(2)F and excess triethylsilane, catalyzed by benzoyl peroxide, leads to the formation of a mixture containing CF(3)CHClF (major), CF(3)CH(2)F, and ClSi(C(2)H(5))(3). On the other hand, the reaction of chlorofluoroalkanes, containing an internal -CCl(2)- group readily proceeds with reduction of both chlorines, leading to compounds such as (CF(3))(2)CH(2) and CF(3)CH(2)C(2)F(5). In contrast to chlorofluoroalkanes, bromofluoroalkanes are much more reactive and reaction with hydrosilane rapidly proceeds without the catalyst at elevated temperature.