Method of producing monohydrogentrihalosilane from the residual silicon obtained from the production of organohalosilanes by means of a metal-catalysed direct process

摘要

Improved yields of monohydrogentrihalosilanes are obtained by contacting the residual silicon obtained from the production of organohalosilanes by means of a metal-catalysed direct process simultaneously with gaseous hydrogen halide and gaseous alkyl halide to give a silicon-residue contact mass, a temperature being selected between about 200 DEG C and about 350 DEG C at which the alkylation of the silicon contact mass is inhibited and at which hydrohalogenation of the silicon contact mass takes place, and the silicon contact mass is heated to the selected temperature. The silicon reacts with the gaseous alkyl halide and the gaseous hydrogen halide at the selected temperature to give improved yields of monohydrogentrihalosilane. In preferred embodiments, monohydrogentrichlorosilane is formed by reacting residual silicon with hydrogen chloride and methyl chloride at a lower temperature than that at which an alkylation reaction with the residual contact mass predominates, so that hydrohalogenation is sufficient to form monohydrogentrichlorosilane.