CN1176090C - Process for preparing alkoxychlorosilane - Google Patents

Abstract

The present invention provides a preparation method for alkoxychlorosilane which is prepared from chlorosilane RnSiCl4-n and alcohol R'OH reacting. A mole ratio of the RnSiCl4-n to the R'OH is 4:1 to 1:1, the reaction temperature is 40 to 80 DEG C., and the reaction time is 4 to 8 hours. In the raw materials of the chlorosilane RnSiCl4-n, wherein R is alkyl, and n is from 0 to 2. The present invention has the advantages of low cost of raw material, high reaction yield, few reaction step, one-step finish, high purity of product, convenient industrial production and no discharge of three waste. The product of the present invention can be used as raw materials for synthesizing alkyl naphthenic base alkoxy silane.

Description

Process for preparing alkoxychlorosilane

Technical Field

The invention relates to a preparation method of a compound, in particular to a preparation method of alkoxy chlorosilane.

Background

The current process for preparing alkoxychlorosilanes is the Grignard process, for example the process for preparing methyl monochlorodimethoxysilane is carried out in two steps, one of which is the preparation of the Grignard reagent with chloromethane CH₃Cl reacts with Mg to generate a Grignard reagent MgCH₃Cl, the second is dimethoxydichlorosilane, and the methyl monochlorodimethoxysilane is prepared by the reaction of dimethoxydichlorosilane and Grignard reagent under the catalysis of iodineA silane. The method has the defects that the yield is low and is generally 30-40%; the cost is high, and the price of the main raw material dimethoxy dichlorosilane is high; the reaction steps are multiple and need two steps to be finished.

Disclosure of Invention

The invention aims to provide a preparation method of alkoxy chlorosilane, which has the advantages of low raw material price, high reaction yield, simple and convenient operation and easy realization of industrialization.

The preparation method of alkoxy chlorosilane of the invention comprises the steps of using chlorosilane RnSiCl_4-nReacting with alcohol R' OH. MOL ratio of reaction RnSiCl_4-nR and OH are 4: 1-1: 1, the reaction temperature is 40-80 ℃, and the reaction time is 4-8 hours. The resulting product alkoxychlorosilane RnSi (OR ")_4-n-1The purity of Cl is generally over 80 percent, and a product with higher purity of over 95 percent can be obtained by rectification. Wherein, the raw material chlorosilane RnSiCl_4-nIn the formula, R is alkyl, preferably methyl or ethyl, n is 0-2, and methyltrichlorosilane is the most representative compound in chlorosilane; the alcohols R' OH are generally alcohols having up to 3 carbon atoms, i.e.alcohols having up to propanol. Chlorosilane RnSiCl_4-nThe chemical reaction equation for reaction with the alcohol R "OH groups is as follows:

the preparation method of alkoxy chlorosilane has the advantages that the price of the used raw materials is low, particularly, the methyl trichlorosilane is industrial waste, and the price is low: the reaction yield is high, generally more than 60 percent, and can reach 80 to 90 percent; the reaction steps are few, the reaction can be completed in one step, and the operation is simple and convenient; and the product purity is high, generally more than 80%, and the product with the purity higher than 95% can be obtained by rectification: no three wastes discharge, easy realization of industrialization, and the product alkoxy chlorosilane can be used as a raw material for synthesizing alkyl cycloalkyl alkoxy silane.

Detailed Description

Example 1: 1660 g of methyltrichlorosilane is added into a feeding tank A of a tower reactor, 620 g of methanol is added into another feeding tank B, the feeding tank A and the feeding tank B are positioned in the middle of the tower reactor, a tower kettle of the reactor is heated, when the temperature is raised to 70-80 ℃, feeding is simultaneously carried out from the feeding tank A and the feeding tank B, a large amount of hydrogen chloride tail gas escapes from the top of the tower, and the feeding speed is controlled to finish feeding of the two materials simultaneously. The total reflux was maintained for a further 5 hours, at which point no hydrogen chloride escaped from the top of the column. The content of methyl monochlorodimethoxysilane is 92.6% by sampling analysis at the bottom of the tower, and the cooled bottom liquid is rectified by a rectifying tower to obtain 960.5 g of a product with the purity of 98%, and the yield is 61.5%.

Example 2: 1310 g of dimethyl dichlorosilane is added into a feeding tank A of a tower reactor, 320 g of methanol is added into another feeding tank B, the feeding tank A and the feeding tank B are positioned in the middle of the tower reactor, a tower kettle of the reactor is heated, when the temperature is raised to 60-70 ℃, feeding is simultaneously carried out from the feeding tank A and the feeding tank B, a large amount of hydrogen chloride tail gas escapes from the top of the tower, the feeding speed is controlled, and two materials are completely fed simultaneously. The total reflux was maintained for another 6 hours, at which point no hydrogen chloride escaped from the top of the column. The content of dimethyl monochloro oxysilane is 82.6% by sampling and analyzing in the tower bottom, the cooled kettle liquid is rectified by a rectifying tower, 840 g of product with the purity of 97.5% is obtained, and the yield is 70%.

Claims (1)

1. A process for preparing alkoxy chlorosilane from chlorosilane R_nSiCl_4-nReacting with alcohol R' OH to obtain alkoxy chlorosilane R_nSi(OR″)_4-n-1Cl, the molar ratio of the reaction being R_nSiCl_4-nR' OH is 4: 1-1: 1, the reaction temperature is 40-80 ℃, the reaction time is 4-8 hours, wherein the raw material chlorosilane R is_nSiCl_4-nWherein R is methyl or ethyl, n is 1-2, and R' OH is an alcohol having 3 or less carbon atoms.