Preparation process of alpha, alpha, alpha ', alpha'-tetrachloro-o-xylene

Abstract

The invention discloses a preparation process of alpha, alpha, alpha ', alpha'-tetrachloro-o-xylene. The preparation process comprises the following steps: adding o-xylene and phosphorus trichloride into a reaction kettle subjected to inert gas replacement; introducing chlorine to react until the alpha, alpha, alpha ', alpha'-tetrachloro-o-xylene in the reaction system reaches a certain content, centrifugally separating out an alpha, alpha, alpha ', alpha'-tetrachloro-o-xylene crude product, then adding the catalyst into the mother liquor again, introducing chlorine to produce, and refining the alpha, alpha, alpha ', alpha'-tetrachloro-o-xylene crude product; adding the catalyst into the mother liquor again and introducing chlorine for production; about 68% o-xylene is converted into alpha, alpha, alpha ', alpha'-tetrachloro-o-xylene; more than 30% of o-xylene is converted into pentachloroo-xylene; the problems of low yield and low crude product content of alpha, alpha ', alpha'-tetrachloro-o-xylene are solved, the product content is effectively increased through refining, the raw material conversion rate is maximized as much as possible, meanwhile, mother liquor which is not completely converted is converted into a byproduct pentachloro-o-xylene again, the problem of organic waste liquor is effectively solved, and benefits can be maximized.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a preparation process for obtaining α, α, α', α'-tetrachloro-o-xylene by chlorination of o-xylene. Background technique [0002] α,α,α′,α′-Tetrachloro-o-xylene can be used to synthesize various medicines and pesticides, and can also be used to synthesize o-phthalaldehyde, which is an important chemical intermediate in industry. At present, the industrial production of α,α,α′,α′-tetrachloro-o-xylene is generally based on o-xylene as raw material, and the side chain is chlorinated under the condition of DMF. After the chlorination reaction is carried out to a certain extent, cooling crystallization. However, the total yield of this process based on ortho-xylene can only reach about 48%, the content of the product obtained by direct chlorination is low, and the waste liquid is also difficult to handle. Contents of the invention [0003] The purpose of the present inven...

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Problems solved by technology

However, the total yield of this process based on o-xylene can only reach about 48%, and the content of the product obtained by direct chlorination is low, and the waste liquid is also difficult to handle

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