Dimethyl dichlorosilane hydrolysis method for directly producing gaseous hydrogen chloride

Abstract

The invention discloses a dimethyl dichlorosilane hydrolysis method for directly producing gaseous hydrogen chloride, and belongs to the technical field of hydrolysis during the production of methyl chlorosilane. The method comprises the following steps of: pre-mixing the dimethyl dichlorosilane and concentrated hydrochloric acid through a jet mixer and then feeding the mixture into a static mixer for hydrolysis of concentrated hydrochloric acid with pressure so as to obtain a reaction mixture; introducing the reaction mixture into a combined separator with a plate type tower; separating the acid oil, acid and gas from the reaction mixture; and processing the acid oil, the acid and the gas respectively. The method ensures complete reaction and complete separation so as to obtain relatively pure hydrogen chloride gas and ensure difficult blockage of a methyl chloride synthesizer and pipelines thereof through forcible hydrolysis of the static mixer and separation of the combined separator with the plate tower in coordination with water removal by condensation; and the hydrogen chloride per se has pressure so as to realize the gravity feed of the hydrogen chloride. The method can obviously improve the product yield; and the unit consumption of the dimethyl dichlorosilane per ton of methyl siloxane is below 1.7 tons.

Description

technical field [0001] The invention belongs to the technical field of hydrolysis in the production process of methylchlorosilane, and in particular relates to a hydrolysis method of dimethyldichlorosilane capable of directly generating gaseous hydrogen chloride. Background technique [0002] Dimethyldichlorosilane is an important step in the production of organosilicon monomers. The methylsiloxane produced by hydrolysis is the main raw material for the production of a series of downstream products of organosilicon. [0003] The hydrolysis of dimethyldichlorosilane is usually hydrolyzed with dilute acid under normal pressure. The dilute hydrochloric acid is forced to circulate in the reaction system under the action of the circulation pump, and the dimethyldichlorosilane is sent into the inlet of the pump, which is realized under the high-speed cutting of the pump impeller. Fully mixed with hydrochloric acid and hydrolyzed, the hydrolyzed product is settled by gravity, hydro...

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Problems solved by technology

[0005] (1) The consumption of raw materials is high, and the unit consumption of dimethyldichlorosilane for the production of methylchlorosilane is above 1.78t

Since the hydrogen chloride generated during hydrolysis is discharged out of the system in the form of hydrochloric acid, part of the hydrogen chloride is removed by the desorption tower and then returned to the system, so the amount of hydrochloric acid discharged from the hydrolysis system is relatively large, and there are 4.2 tons of hydrochloric acid for every 1t of dimethyldichlorosilane consumed. Outflow, due to the limitation of hydrochloric acid settling time in the hydrolysis system, some siloxanes in the effluent hydrochloric acid have not been separated, and it needs to settle for more than 50 hours before it can be used for desorption. The siloxanes separated by sedimentation are all in acid Polymerized into polymers with higher molecular weight under the same conditions, the market value is lower

Moreover, siloxane in hydrochloric acid will also accumulate on the inner wall of the pipeline, causing pipeline blockage

[0006] (2) Because hydrogen chloride dissolves in water is a strong exothermic process, the hydrolysis process needs to be cooled with a large amount of water, and an average of 50 tons of cooling water is required for hydrolysis per ton of dimethyldichlorosilane. Because the hydrolysis temperature should not be too high, it cannot be used Circulating water is used as the coolant. If there is no low-temperature natural water and chilled water is used as the coolant, the energy consumption will be greater

[0008] (4) Since the hydrochloric acid discharged from hydrolysis needs to be settled, it is necessary to set up more large-volume hydrochloric acid settling tanks, which need to occupy a large area of ​​land for layout, and the polymers polymerized in hydrochloric acid need to be cleaned regularly. The emitted hydrogen chloride will cause certain pollution to the atmosphere

[0009] In view of the above defects in dilute acid hydrolysis, domestic enterprises have introduced concentrated acid hydrolysis technology from abroad, but there are disadvantages of low pressure of hydrogen chloride gas, low purity of hydrogen chloride gas, and expensive equipment, and industrial production is not very stable.

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