Process for preparing 4,4'-dichlorodiphenylsulfone employing sulfoxide oxidation method

Abstract

The invention relates to a process for preparing 4,4'-dichlorodiphenylsulfone, in particular to a process for preparing 4,4'-dichlorodiphenylsulfone employing a sulfoxide oxidation method. The process comprises the following steps: carrying out friedel-crafts reaction with chlorobenzene and thionyl chloride under the action of a catalyst to obtain the 4,4'-dichlorodiphenylsulfone; dissolving the obtained 4,4'-dichlorodiphenylsulfone with a solvent; adding hydrogen peroxide and carrying out oxidation reaction to obtain a 4,4'-dichlorodiphenylsulfone crude product; carrying out secondary oxidation refining on the obtained 4,4'-dichlorodiphenylsulfone crude product; and finally preparing high-purity 4,4'-dichlorodiphenylsulfone. The purity of the 4,4'-dichlorodiphenylsulfone purified by the refining process is greater than 99.5%; the refining yield is greater than 98.5%; and the process completely meets the synthesis requirements of high-performance polymers.

Description

technical field [0001] The invention relates to a process for preparing 4,4'-dichlorodiphenyl sulfone, in particular to a process for preparing 4,4'-dichlorodiphenyl sulfone by a sulfoxide oxidation method. Background technique [0002] 4,4'-Dichlorodiphenylsulfone (DDS) is an important chemical monomer, the main raw material for the preparation of engineering plastics such as polysulfone and polyethersulfone, and an intermediate for medicine, dyes and pesticides. A variety of polymer products can be prepared from it, such as resins such as bisphenol A polysulfone, polyphenylene ether sulfone, and polyamide sulfone, and it is also a raw material for the preparation of leprosy drug intermediate 4,4'-diaminodiphenylsulfone. With the wide application of polymer materials, the demand for DDS is also increasing. [0003] There are many ways to produce DDS in industry, such as sulfuric acid method, chlorosulfonic acid method, sulfur trioxide method and sulfoxide oxidation method....

AI Technical Summary

Problems solved by technology

The sulfuric acid method has low cost and simple raw materials, but the conversion rate is low, the reaction time is long, the melting point of the product is low, and the quality is not good

The chlorosulfonic acid process is relatively mature, and the product quality is good, but the production cost is high and the three wastes are serious

The preparation of DDS by sulfur trioxide method is an improved method, which is adopted by UCC Company in the United States. It uses sulfur trioxide sulfonation and thionyl chloride acyl chloride route, and the process is relatively complicated.

However, during the oxidation process of dripping hydrogen peroxide, solid crystals are continuously precipitated, and part of the 4,4'-dichlorodiphenyl sulfoxide is wrapped inside the crystals before being oxidized, resulting in incomplete oxidation.

However, traditional refining methods cannot effectively remove unoxidized 4,4'-dichlorodiphenylsulfoxide

[0005] The impurity in crude 4,4'-dichlorodiphenyl sulfone is mainly unoxidized 4,4'-dichlorodiphenyl sulfoxide, both of which have high boiling points and are not suitable for purification by distillation

And general solvent recrystallization method, product yield is low, and product quality is difficult to guarantee