Method for preparing hexamethyldisiloxane by using organic silicon by-product

Abstract

The invention provides a method for preparing hexamethyldisiloxane by using an organic silicon by-product. According to the method, the organic silicon by-product chlorotrimethylsilane and recycled washing diluted hydrochloric acid are subjected to hydrolysis under a certain condition, hydrogen chloride gas generated by hydrolysis is removed through reverse blowing of compressed air, after reaction is compelled, the product is left to stand for layering, and an upper solution is washed with water for multiple times for deacidification and then rectified at normal pressure, so that the hexamethyldisiloxane finished product is obtained. Practice proves hexamethyldisiloxane prepared through the method provided by the invention is stable in quality, simple in process and easy to produce industrially and the comprehensive utilization value of the organic silicon by-product chlorotrimethylsilane is increased greatly.

Description

technical field [0001] The invention belongs to the technical field of organosilicon by-product production, and in particular relates to a method for preparing hexamethyldisiloxane by utilizing organosilicon by-product trimethylmonochlorosilane. Background technique [0002] With the rapid development of the organosilicon industry, the output of organosilicon chlorosilane monomers is also increasing. It is estimated that by the end of this year, the total production capacity of domestic organosilicon monomer manufacturers will be about 2500kt / a. Trimethylchlorosilane is one of the by-products of the production of organosilylchlorosilane monomers, accounting for about 3% of monomer production capacity. The molecular structure contains Si-Cl bonds. Therefore, it is necessary to comprehensively utilize the substance from the aspects of saving production cost and safety and environmental protection. [0003] Hexamethyldisiloxane is an important primary raw material for organosi...

AI Technical Summary

Problems solved by technology

Chinese patent CN101362777A has invented a method for preparing hexamethyldisiloxane, by reacting trimethylmonochlorosilicon with carbonate, and then collecting hexamethyldisiloxane by steaming. The process of this method is simple, but Due to the addition of solid salts in the preparation process, it is difficult to purify and recycle, and the cost is high, which limits the application of this technology; Chinese patent CN103951692A provides a method for preparing high-purity and high-quality hexamethyldisiloxane. Chlorotrimethylsilane is added dropwise to the hydrolysis reaction kettle pre-added with water and condensation catalyst to react. The hydrolyzate is divided into three layers after standing, and the hydrolyzate in the upper layer is washed with water, neutralized with alkali solution, dewatered, filtered, Fractional distillation obtains hexamethyldisiloxane with a higher mass fraction. This method uses a condensation catalyst to promote the efficiency of the hydrolysis reaction, and the prepared product has a higher mass fraction. However, the technical process is long, complicated, and involves operations such as filtration. , which reduces the yield of hexamethyldisiloxane to a certain extent, which limits the promotion of this technology