DIRECT SYNTHESIS OF TRIS(CHLOROSILYL)METHANES CONTAINING SI-H BONDS

Direct reaction of elemental silicon with a mixture of chloroform and hydrogen chloride has been studied in the presence of a copper catalys t using a stirred reactor equipped with a spiral band agitator at vari ous temperatures from 280 to 340 degrees C. Tris(chlorosilyl)methanes 1a-e with Si-H bonds were obtained as the major products along with by products of bis(chlorosilyl)methanes, derived from the reaction of sil icon with methylene chloride formed by the decomposition of chloroform , and trichlorosilane and tetrachlorosilane produced from the reaction of elemental silicon with hydrogen chloride. The decomposition of chl oroform was suppressed and the production of polymeric carbosilanes re duced by adding hydrogen chloride to chloroform. The deactivation prob lem of elemental silicon due to the decomposition of chloroform and po lycarbosilanes was eliminated. Cadmium was a good promoter for the rea ction, while zinc was found to be an inhibitor for this particular rea ction.