The direct synthesis of methylchlorosilanes by reacting metallic silicon with methyl chloride in the presence of a copper catalyst yields low-boiling component,high-boiling component and methyltrichlorosilane as by-products. The proposed process for prepares monosilanes from the HBC fraction by reacting it with hydrogen chloride in the presence of an amine or amide catalyst. The conversion of disilanes into monosilanes is above 80% in general and the best is 86%.A method is also proposed for preparing dimethyldichlorosilane from methyltrichlorosilane,reacting simultaneously with the LBC components having a high content of methyl groups and with the HBC non-cleavable components,in the presence of a catalyst,in which the best conversion is 66.2%,and the best content of dimethyldichlorosilane in final products is 46.4%.
