Chlorine resource recycling method and system for chloroacetyl chloride chlorination reaction process

Abstract

The invention discloses a chlorine resource recycling method for the chloroacetyl chloride chlorination reaction process. The method includes the steps that a by-product hydrogen chloride waste gas generated in the production process of trichloroacetic acid chloride by means of the chloroacetyl chloride chlorination reaction is introduced into a hydrogen chloride purification tower from the lower portion of the hydrogen chloride purification tower, and makes contact with absorption liquid in a countercurrent mode in the hydrogen chloride purification tower, and the absorption liquid adsorbs and removes organic impurities in the hydrogen chloride gas; the hydrogen chloride waste gas absorbed and purified and oxygen are subject to a catalytic oxidation reaction under the effect of an oxidation catalyst, and hydrogen chloride is catalyzed, oxidized and converted into chlorine gas; mixed gas generated after hydrogen chloride is oxidized is frozen by means of freezing saline water to exchange heat, water vapor in the mixed gas is condensed into liquid water, and hydrogen chloride which is not subjected to the reaction is dissolved into the liquid water to form waste hydrochloric acid; the mixed gas which is frozen and dewatered is directly used in the production process of trichloroacetic acid chloride by means of the chloroacetyl chloride catalytic chlorination. The method has the advantages that the technology is simple, equipment investment cost is low, and oxygen does not need to be separated when the catalyzing chlorination reaction is carried out.

Description

technical field [0001] The invention belongs to the field of recycling of chlorine resources, and relates to a method and system for recycling chlorine resources in the chlorination reaction process of monochloroacetyl chloride, specifically absorbing and purifying the hydrogen chloride by-product of monochloroacetyl chloride, catalytic oxidation, and freezing to remove water Finally, the chlorine resource recycling method and system for directly recycling the catalytic chlorination of monochloroacetyl chloride to produce trichloroacetyl chloride. Background technique [0002] Since the global demand for chlorpyrifos reaches 200,000 tons and increases at a rate of 10% every year, the demand for the key intermediate of synthetic chlorpyrifos, sodium clopyridinate, is extremely strong. Trichloroacetyl chloride is one of the main raw materials for the synthesis of the pesticide chlorpyrifos intermediate, triclopyridyl sodium. [0003] The patent (CN1122324A) has reported that ...

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Problems solved by technology

Literature (Jiang Fenfang, Zhejiang Chemical Industry, 1999, 30 (4): 30-31) reports that tetrachloroethylene is used as a starting material, and trichloroacetyl chloride is obtained through liquid-phase catalytic oxidation, but in this process, in order to make the boiling point close to The separation of tetrachlorethylene and trichloroacetyl chloride requires the further chlorination of unreacted tetrachlorethylene to hexachloroethane, resulting in a waste of raw materials

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