Method for preparing polyorganosiloxane and gas phase hydrogen chloride by multi-stage continuously hydrolyzing dichlorosilane

Abstract

The present invention relates to continuous multistage organic dichlorosilane hydrolyzing process for preparing organic siloxane polymer and gaseous hydrogen chloride. Organic dichlorosilane is hydrolyzed continuously in a circulating hydrolysis reaction system with at least thee stages, each of which includes one inner circulating unit and one outer circulating unit. In the relatively independent hydrolysis reaction stages, the hydrolyzed organic siloxane polymer is fed continuously from the upper stage to the lower stage through one degasser to eliminate great amount of free hydrogen chloride, while hydrolyzed hydrochloric acid is replenished from the lower stage to the upper stage. The present invention has low gaseous hydrogen chloride content in each hydrolysis reaction stage, easy operation, stable product quality, high yield and stable pressure of anhydrous gaseous hydrogen chloride.

Description

technical field [0001] The invention relates to a method for preparing polyorganosiloxane and gas phase hydrogen chloride by multistage continuous hydrolysis of organodichlorosilane. Background technique [0002] Organodichlorosilane is the main product of organosilicon monomer synthesis, such as dimethyldichlorosilane, and the low-viscosity linear or cyclic organosiloxane prepared by hydrolysis of organodichlorosilane is the main raw material of polyorganosiloxane , Polyorganosiloxane is widely used in electronics, daily chemicals, electric power, building materials and other industries. [0003] Chinese patent CN1209823A discloses the hydrolysis of organodichlorosilane in concentrated hydrochloric acid to obtain low-viscosity polyorganosiloxane, but there are still certain defects in engineering scale-up, such as the separation of oil and acid-water two-phase interface, the There are still some disadvantages in the removal and absorption of entrained hydrogen chloride gas...

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Problems solved by technology

[0003] Chinese patent CN1209823A discloses the hydrolysis of organodichlorosilane in concentrated hydrochloric acid to obtain low-viscosity polyorganosiloxane, but there are still certain defects in engineering scale-up, such as the separation of oil and acid-water two-phase interface, the There are still some defects in the removal and absorption of entrained hydrogen chloride gas

However, in this production process, the update of the oleic acid two-phase interface is not timely, which affects the speed of the hydrolysis reaction. In the phase separator, the oil phase stays for a relatively long time, and the polymerization reaction is still prone to occur in the primary and secondary hydrolysis reaction systems. The hydrogen chloride gas content in the pressurized crude hydrolyzate from the hydrolysis reaction system is high, which makes the hydrochloric acid content in the next hydrolysis process high, which affects the hydrolysis reaction of the next stage, and then affects the product yield and product quality stability.

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