Preparation method of methyldimethoxysilane

Abstract

The invention relates to the technical field of fine chemical engineering, and in particular relates to a preparation method of methyldimethoxysilane. The preparation method disclosed by the invention is characterized in that methyldichlorosilane and methanol sufficiently react in a packed tower by adopting a one-step esterification process, and Si-Cl bonds of methylhydrochlorosilane are completely converted into Si-O bonds, and the reaction efficiency is high; after the reaction is ended, a crude product is neutralized by hexamethylenetetramine, and then is filtered and distilled and the like to obtain a methyldimethoxysilane product with the mole yield of 99.5 percent or above. The mole yield of a product prepared by the preparation method disclosed by the invention reaches 95.0 percent or above, and the product is neutral, so the use of downstream customers is not affected; in addition, a used neutralizer does not react with the methylhydrochlorosilane or the methyldimethoxysilane product; by-produced hexamethylene tetramine hydrochloride does not cake, is proper in particle size and easy to filter, and is suitable for industrial production.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a preparation method of methyldimethoxyhydrogensilane. Background technique [0002] Methyldimethoxyhydrogensilane contains both hydrolyzed alkoxy linkages (Si-OCH 3 ), which also contains active silicon-hydrogen bonds (Si-H), where Si-OCH 3 The bonds are converted into siloxanes through hydrolysis and condensation; reacting with Grignard reagents can generate organoalkoxysilanes; Si-H bonds can undergo hydrosilylation with a series of unsaturated compounds such as alkenes and alkynes under platinum catalysts Synthetic reaction to obtain various silicone coupling agents, silicone-terminated and cured polyethers, polyacrylate sealants and adhesives, etc., and is suitable for the preparation of many high-purity silicone compounds, such as modified silanes Sealants, anti-fogging agents, water repellents, silane coupling agents such as vinyl, epoxy and methacryloxy derivativ...

AI Technical Summary

Problems solved by technology

[0004] The first method is the esterification method: that is to use methylhydrogendichlorosilane and methanol as raw materials, and carry out esterification reaction under the action of solvent and hydrochloric acid absorbent to synthesize methyldimethoxyhydrogensilane products. Both are in the stage of small laboratory tests, but because the selected hydrochloric acid adsorbent forms a complex with chlorosilane, the absorbent forms a precipitate with HCl on the one hand, and complexes with methyldichlorohydrogensilane on the other hand. Chlorosilane cannot be released from the complex well, and due to the generation of precipitation, the reaction complex product is wrapped, making the reaction uneven. Therefore, the product yield decreases after the absorbent is used, resulting in methyl di The synthesis process of methoxyhydrosilane has not been industrialized

[0005] The second method is the group exchange method: that is to use methyltrimethoxysilane and methyldichlorohydrosilane to carry out group exchange reaction to synthesize methyldimethoxyhydrogensilane products, such as the patent introduction of CN 1410431A , the group exchange process has advantages in principle and process over the above-mentioned esterification process. After reading the patent literature carefully, it can be learned that the methyl dimethoxyhydrosilane product synthesized according to the method provided by the patent must contain methyl A methoxyhydrochlorosilane component, so the synthesized product is acidic, which affects the use of downstream products

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