Method for preparing dichlorodimethylsilane by virtue of disproportionation

Abstract

The invention discloses a method for preparing dichlorodimethylsilane by virtue of disproportionation. The method comprises the following steps: enabling aluminum trichloride, a 1-propyl-triethoxysilyl-imidazole chloride ionic liquid, fluorine intercalated hydrotalcite, aluminum trichloride and alcohol to react; obtaining a composite catalyst of fluorine intercalated hydrotalcite loaded aluminum trichloride and an ionic liquid after completing reaction; and adding methyltrichlorosilane, trimethylsilyl chloride and the composite catalyst into a high-pressure reaction kettle, and reacting to obtain dichlorodimethylsilane. The method disclosed by the invention has the advantages of good catalyst activity, cyclic utilization, small three wastes (waste gas, waste water and waste residues) and environment-friendly.

Description

technical field [0001] The invention relates to a method for preparing organosilicon, in particular to a method for preparing dimethyldichlorosilane by disproportionation. Background technique [0002] The strength of organosilicon monomer production technology directly affects the development of the entire organosilicon industry. Dimethyldichlorosilane ((CH 3 ) 2 SiCl 2 , referred to as dimethyl) is one of the most important monomers, and its consumption accounts for about 80% of the whole monomer production. Most factories will produce more by-products such as monomethyltrichlorosilane (abbreviated as monomethyl, accounting for 10-15%) and trimethylchlorosilane (abbreviated as trimethyl, accounting for 1%) when preparing dimethyl by direct method, but they The use of hydrogen chloride is limited, and direct discharge is easy to react with moisture in the air to form hydrogen chloride, polluting the environment, and there are many inconveniences in long-term storage. It...

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Problems solved by technology

[0006] The catalysts used in existing patents and literature technologies, amines are used as catalysts, and the reaction conditions are mild and the process is mature, but the selectivity of dimethyl is not good; when phosphate is used as a catalyst, the selectivity of dimethyl is not good; AlCl 3 As a catalyst, the selectivity of dimethylformamide is good, but the reaction needs high temperature and high pressure, which requires high process equipment

while the AlCl 3 However, in the above patents, activated carbon, clay, ZSM molecular sieve and other carriers are selected, and the surface is hydrophilic, which is relatively compatible with the disproportionated reactants - methyltrichlorosilane and trimethylchlorosilane. Poor, AlCl inside micropores 3 The catalytic reaction cannot be carried out, thereby reducing the catalytic activity