PREPARATION OF ALKYLMONOHYDROGENOHALOGENOSILANES BY REDISTRIBUTION FOLLOWED BY DISTILLATION AND ASSOCIATED DEVICE

摘要

The invention concerns a method for obtaining alkylmonohydrogenohalogenosilanes (AHHS), for example Me2HSiCl. Said AHHS are prepared by redistribution from MeHSiCl2 and Me3SiCl, in the presence of a catalyst such as AlCl3, which can start a parasitic disproportionation which affects the AHHS produced. In order to avoid this, the method consists in using an inhibitor which neutralises AlCl3 after redistribution. The problem which still prevails and on which the present invention is based is related to the fact that during distillation, which aims at separating the required AHHS, the latter are again subjected to the parasitic disproportionation. In order to solve this problem, the invention proposes a method for preparing AHHS comprising steps (a) of redistribution, (b) use of an inhibitor of AlCl3 and (c) separating and collecting by distillation AHHS formed in the raw reaction mixture of redistribution using three distillation columns I, II, III and proceeding in such a way that, at least in one part of the distillation circuit, the AHHS aimed at are in the presence of the AlCl3 inhibitor. Advantageously, the inhibitor is injected in the reflux of column I top. The invention also concerns a train of three distillation columns comprising means for injecting the AlCl3 inhibitor.