Clean production method for improving reaction yield of 2, 4-dichloroacetophenone

Abstract

The invention relates to a clean production method for improving the reaction yield of 2, 4-dichloroacetophenone, which comprises the following steps: S1, separating and extracting m-dichlorobenzene by using chlorinated aromatic hydrocarbon waste; S2, preparing crude 2, 4-dichloroacetophenone; and S3, separating and purifying the crude 2, 4-dichloroacetophenone to obtain a dichloroacetophenone product. The method has the advantages that the optimal reaction conditions are found through the influence of the feeding ratio, the reaction temperature, the reaction time, different Lewis acids and the AlCl3 dosage on the product yield, the purity and the yield of the product are guaranteed, the purity of the product can reach 99.5% or above, and the yield of the product can reach 65% or above.

Description

technical field [0001] The invention relates to a production method of 2,4-dichloroacetophenone, in particular to a clean production method for improving the reaction yield of 2,4-dichloroacetophenone. Background technique [0002] 2,4-Dichloroacetophenone is the raw material for the preparation of ω-bromo-2,4-dichloroacetophenone or ω-2,4-trichloroacetophenone, the latter two are used for the preparation of imazalil and propane It is the intermediate of fungicides such as azole and etoconazole, and it is also the intermediate of insecticide chlorpyramid and herbicide wild swallow. [0003] Generally, the method for synthesizing 2,4-dichloroacetophenone is to adopt m-dichlorobenzene as a raw material, use acetyl chloride as an acylating agent to obtain 2,4-dichloroacetophenone crude product through Fridel-Crafts acylation, and then pass through Purification gives a relatively pure product. Acetyl chloride has certain disadvantages as an acylating agent. The boiling point o...

AI Technical Summary

Problems solved by technology

[0005] In order to meet the market's demand for products, a production method for producing 2,4-dichloroacetophenone using m-dichlorobenzene as a raw material and acetic anhydride as an acylating agent has been developed. After searching, the patent CN 102675073 A discloses A production method of 2,4-dichloroacetophenone, which mainly consists of five steps of acylation, hydrolysis, water washing, distillation, and crystallization. The acylation reaction is: m-dichlorobenzene in the presence of anhydrous aluminum trichloride Acylation reaction with acetic anhydride under action; this invention utilizes m-dichlorobenzene as raw material, acetic anhydride as acylating agent, adopts A1C1 3 For the catalyst reaction to produce 2,4-dichloroacetophenone, the resulting product is higher than that of acetyl chloride as an acylating agent; acetic anhydride is used as an acylating agent, and A1C1 is used 3 As a catalyst, 2,4-dichloroacetophenone is produced by using meta-dichlorobenzene extracted from chlorinated aromatic wastes as a raw material, which not only solves the problem of disposal of by-products in the chlorination process of benzene, but also improves the chlorination process. The recycling rate of aromatics has high social benefits and economic value; but there are still some defects: through this process technology scheme, the product conversion rate is relatively low