Direct synthesis of tris(chlorosilyl)methanes containing Si-H bonds

Abstract

Direct reaction of elemental silicon with a mixture of chloroform and hydrogen chloride has been studied in the presence of a copper catalyst using a stirred reactor equipped with a spiral band agitator at various temperatures from 280 to 340 degrees C. Tris(chlorosilyl)methanes 1a-e with Si-H bonds were obtained as the major products along with byproducts of bis(chlorosilyl)methanes, derived from the reaction of silicon 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 chloroform was suppressed and the production of polymeric carbosilanes reduced by adding hydrogen chloride to chloroform. The deactivation problem of elemental silicon due to the decomposition of chloroform and polycarbosilanes was eliminated. Cadmium was a good promoter for the reaction, while zinc was found to be an inhibitor for this particular reaction.