Preparation method of alkoxy silane

Abstract

The invention relates to a preparation method of alkoxy silane. According to the method, silicon waste is used as a raw material, the raw material comprises a rectified liquid high-boiling residue anda byproduct silica powder, and the rectified liquid high-boiling residue is mainly composed of trichlorosilane, silicon tetrachloride and high polymers thereof; when the rectified liquid high-boilingresidue is used as a raw material, anhydrous alkoxy alcohol and the rectified liquid high-boiling residue are directly added into a reactor to react; when the byproduct silica powder is used as a rawmaterial, a novel composite catalyst system is formed by adopting a copper-based catalyst and an auxiliary agent, the silica powder and the composite catalyst are pretreated, a mixture and anhydrousalkoxy alcohol are uniformly dispersed in a suspending agent, and a direct synthesis reaction is carried out in the reactor. According to the method, the utilization way of the silicon waste is widened, and high-added-value utilization of the silicon waste is achieved; in addition, the use amount of alkoxy alcohol is also reduced, the conversion rate of the silicon waste is improved, and the purity and yield of the product are improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of alkoxysilane, and in particular relates to a preparation method of alkoxysilane. Background technique [0002] Alkoxysilane is a very important organosilicon raw material. It is the basic raw material for the preparation of silane compounds, organosilicone polymers, colloidal silica, silylation agents and ceramics. It is widely used in precision casting, white carbon black manufacturing, It can also be used as an olefin polymerization catalyst and crosslinking agent in the fields of adhesives, coatings and special coatings, and has developed rapidly in recent years. [0003] So far, the method for industrially preparing alkoxysilane usually adopts the alcoholysis method of chlorosilane, for example, firstly, metal silicon is reacted with chlorine to prepare silicon tetrachloride, and then silicon tetrachloride is prepared by ethanol alcoholysis to ethyl orthosilicate, Its reaction formula ...

AI Technical Summary

Problems solved by technology

However, its disadvantages are that the conversion rate of silicon powder is low, the cost is high, and it is not easy to operate.

[0014] In the prior art, the disadvantage of using silicon powder and alcohols to prepare alkoxysilanes is that the selected suspending agents are organic substances such as inert alkyl-substituted aromatic mixtures, high-temperature heat-conducting oils or diphenyl ethers. Although these suspending agents are inert, But it does not mean that there is no reaction, and at the same time, impurities will be brought in to contaminate the reaction product

And its intermittent-continuous production process brings certain difficulties to the process operation of the device, the stability of the device becomes poor, and the conversion rate of silicon powder and the selectivity of the target product will be affected accordingly.

[0015] In addition, in the process of producing polysilicon by using the Siemens method, it has to go through many links such as silicon powder preparation, cold hydrogenation, rectification and purification, hydrogen reduction and tail gas recovery, and each link will produce some "waste", which cannot continue to be recycled. Continued recycling in polysilicon production systems

For example, during the preparation of silicon powder, polysilicon enterprises with an annual output of 50,000 tons will screen out more than 3,000 tons of fine silicon powder every year. During rectification and purification, tens of thousands of tons of high-boiling distillation will also be produced. Bringing serious safety hazards and environmental pressure, especially the high boiling of rectification, the company has to invest a lot of manpower, material and financial resources every year to deal with it. Therefore, the company urgently needs to find a greener and lower investment waste utilization technology and method

Images