Chloroacetic acid chlorination mother solution treatment method

Abstract

The invention discloses a chloroacetic acid chlorination mother solution treatment method, comprising the following steps of heating a chlorination mother solution through a heater; delivering the heated chlorination mother solution and water into a hydrolysis reactor respectively, and evaporating a part of acetyl chloride; reacting the other part of acetyl chloride with water; delivering the hydrolyzed chlorination mother solution into a secondary hydrolysis reactor, and performing flash evaporation to separate HCL out; pumping the mother solution subjected to the flash evaporation into a hydrogenation reactor through a pump, reacting in the presence of a catalyst, delivering HCL after reacting into an absorption device, and performing a distillation or crystallization process on the mother solution. The method has the advantages that acetyl chloride in the chlorination mother solution is recycled, so that the consumption of acetic anhydride in production is finally reduced, the HCL content of the chlorination mother solution is reduced, and the hydrogenation reaction efficiency is improved.

Description

Technical field [0001] The invention relates to a production method of chloroacetic acid, in particular to a processing method of chloroacetic acid chlorination mother liquor. Background technique [0002] There are only two industrial production methods for chloroacetic acid: trichloroethylene hydrolysis and acetic acid catalytic chlorination. The hydrolysis of trichloroethylene uses concentrated sulfuric acid as a catalyst to carry out the addition and hydrolysis of water at the same time. The hydrolysis of trichloroethylene has been developed due to its simple process and high product purity. Europe used this process to build industrial production equipment, but it has been eliminated in recent years due to expensive raw materials. The acetic acid catalytic chlorination method is under the action of a catalyst (such as iodine, phosphorus, sulfur or sulfur and phosphorus halides and acetic anhydride, etc.), glacial acetic acid and chlorine are in one or several series reactors...

AI Technical Summary

Problems solved by technology

The trichlorethylene hydrolysis method has been developed due to its relatively simple process and high product purity. This process was used to build industrial production plants in Europe, but it has been eliminated in recent years due to expensive raw materials.

But this method has following shortcoming: 1) acetyl chloride content is higher in the chlorination mother liquor, after directly adding water and hydrolyzing, finally cause the unit consumption of acetic anhydride to be high; The by-products of the hydrogenation reaction increase and the product yield decreases; 3) The chlorination mother liquor contains high HCL, which affects the efficiency of the hydrogenation reaction and leads to an increase in catalyst consumption

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