Method for purifying dimethylchlorosilane by extraction and distillation

The invention discloses a method for purifying dimethylchlorosilane, which is to add an extractant to extract and distillate a low-boiling mixture produced in a process for producing methyl chlorosilane by a direct method to separate the dimethylchlorosilane, wherein extractant is an apolar aprotic solvent having a boiling point of no less than 70 DEG C. The extraction and distillation method adopted can effectively separate a hydrocarbon of 2-methyl-2-butylene having a boiling point similar to that of the dimethylchlorosilane, so the method for purifying the dimethylchlorosilane by extraction and distillation breaks a limit of the conventional distillation purification method that the maximum content of the dimethylchlorosilane is less than 88 percent, achieves a content of the dimethylchlorosilane in distillation of up to 95 percent, even 98 percent.