Synthesis of Tris(silyl)methanes by Modified Direct Process

摘要

Direct reaction of elemental silicon with a mixture of (dichloromethyl)silanes 1 [Cl-nMenSiCHCl: n = 0 (a), n = 1(b), n = 2(c), n = 3(d)] and hydrogen chloride has been studied in the presence of copper catalyst using a stirred bed reactor equipped with a spiral band agitator at various temperatures from 240∩ to 340∩. Tris(si-lyl) methanes with Si-H bonds, 3a-d [Cl-nMenSiCH(SiHCl)], and 4a-d [Cl-nMenSiCH(SiHCl)(SiCl)], were obtained as the major products and tris(silyl)methanes having no Si-H bond, 5a-d [Cl-nMenSiCH(SiCl)], as the minor product along with byproducts of bis(chlorosilyl)methanes, derived from the reaction of silicon with chloromethylsilane formed by the decomposition of 1. In addition to those products, trichlorosilane and tetra-chlorosilane were produced by the reaction of elemental silicon with hydrogen chloride. The decomposition of 1 was suppressed and the production of polymeric carbosilanes reduced by adding hydrogen chloride to 1. Cad-mium was a good promoter for and the optimum temperature for this direct synthesis was 280∩.