[BMIM]Cl-nAlCl3 ionic liquid-catalyzed redistribution reaction between methyltrichlorosilane and low-boiling residue to dimethyldichlorosilane

Methyltrichlorosilane and low-boiling residue from the synthesis of methylchlorosilanes via the direct reaction of silicon and methyl chloride were effectively converted to high-valued dimethyldichlorosilane catalyzed by 1-butyl-3-methylimidazolium chloroaluminate, [BMIM]Cl-nAlCl3, ionic liquid catalysts. The yield of dimethyldichlorosilane reached 69.1% when the redistribution reaction between methyltrichlorosilane and low-boiling residue was catalyzed by [BMIM]Cl-6AlCl3 at a reaction temperature of 150 °C for 300 min. The conversion of methyltrichlorosilane was 87.8%. And the conversions of tetramethylsilane, methylhydrodichlorosilane, and dimethylhydrochlorosilane present in low-boiling residue were ca. 100%, respectively. The ionic liquids could be recycled efficiently. This research provided an eco-friendly and economical route for the treatment of methyltrichlorosilane and low-boiling residue, which were the by-products in the direct synthesis of methylchlorosilanes. The possible reaction route was also discussed.