Method for synthesizing phenyl methyl dialkoxyl silane with high selectivity

Abstract

The invention relates to a method for synthesizing phenyl methyl dialkoxyl silane with high selectivity. The structural formula of phenyl methyl dialkoxyl silane is PhMeSi(OR)2, in which R is alkyl with 1-6 carbons. The method is characterized by comprising the following steps of: performing reaction with methyl trialkoxyl silane based on non-cyclic ether compounds such as ethyl ether as a reaction liquor and a bromobenzene Grignard reagent as a raw material; and then, obtaining the target compound, i.e., phenyl methyl dialkoxyl silane with high selectivity and high yield through simple filtering and fractional purification, and meanwhile, greatly inhibiting the generation of a byproduct diphenyl methyl alkoxyl silane.

Description

technical field [0001] The invention belongs to the field of organosilicon chemical industry, and in particular relates to a synthesis method of polysiloxane industrial monomer, that is, phenylmethyldialkoxysilane. This monomer has a particularly important application in the synthesis of high-performance polymethylphenylsiloxane. Background technique [0002] Phenylsilane is an important monomer in the organosilicon chemical industry. Its consumption is second only to methylsilane monomer. It is one of the basic raw materials for the synthesis of phenyl silicone oil, phenyl silicone rubber and phenyl silicone resin. For polysiloxane obtained from methylsilane monomer, after introducing a certain proportion of phenyl monomer into its main chain, it can endow it with excellent high and low temperature resistance, radiation resistance and physical and mechanical properties, and can also improve Its compatibility with organic compounds and inorganic fillers increases the refrac...

AI Technical Summary

Problems solved by technology

[0014] Although this method solves the shortcomings of high reaction temperature in the synthesis of phenylmethyldialkoxysilane by the one-step Grignard reagent method, but because the reaction must use tetrahydrofuran as a solvent, the magnesium salt generated by the reaction in this solvent Filtration of by-product alkoxymagnesium chloride is very difficult

Although it is possible to remove part of THF by distillation, and then add xylene and continue distillation to remove the remaining THF, but due to the strong coordination between these magnesium salts and THF, it is difficult to completely remove THF by distillation.

Moreover, heating a mixture containing a large amount of magnesium salt residue and reaction products can seriously affect the heat and mass transfer during heating

In this case, overheating is easy to occur, and other side reactions occur, affecting the yield and purity of the target product

As a result, the yield of the phenylmethyldialkoxysilane obtained by this method is low, and a large amount of diphenyl substituted by-products are generated, that is, the reaction selectivity is very poor

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