Method for preparing chlorobenzene, p-dichlorobenzene and o-dichlorobenzene in benzene chlorination

Abstract

The invention discloses a method for preparing chlorobenzene, p-dichlorobenzene and o-dichlorobenzene in benzene chlorination, and relates to a preparation method of chemical raw materials. The method comprises the following steps: continuously introducing dry benzene and chlorine with a high activity and high p-dichlorobenzene selectivity catalyst into an outer circulation reactor, wherein the benzene and chlorine need sufficient retaining time, reacting at a set temperature to prepare p-dichlorobenzene, obtain o-dichlorobenzene at the same time and co-produce chlorobenzene, preparing dichlorobenzene by using the outer circulation reactor and taking the benzene and the chlorine as raw materials and metal sulfide as a catalyst, at the same time co-producing chlorobenzene, forming circulation of the materials through the introduced nitrogen and generated hydrogen chloride as power so as to obtain good stirring for prompting mixing, diffusion, heat conduction and mass transfer of the reactants. The method is rapid in reaction speed, high in capacity, large in ratio of p-dichlorobenzene and o-dichlorobenzene, free of polychlorobenzene byproduct, and high in flexibility and operation flexibility as the ratio of the chlorobenzene to the dichlorobenzene in a product can be adjusted according to demands.

Description

technical field [0001] The invention relates to a method for preparing chemical raw materials, in particular to a method for simultaneously preparing chlorobenzene, p-dichlorobenzene and o-dichlorobenzene through chlorination of benzene. Background technique [0002] P-dichlorobenzene is an important raw material for organic chemical synthesis. It is widely used as a pesticide intermediate, as a fumigant insecticide, fabric mothproof agent, mildewproof agent, and air deodorizer. Most of it is used to make sanitary balls. For example, 32% of p-dichlorobenzene is used as deodorant in the United States. Western Europe accounted for 50%. In Japan, p-dichlorobenzene used for deodorant and anti-moth agents accounts for 70% of its total production capacity; [0003] An important use of p-dichlorobenzene is as an intermediate of high-performance engineering plastic polyphenylene sulfide. Polyphenylene sulfide has excellent properties such as high temperature resistance, radiat...

AI Technical Summary

Problems solved by technology

The current production method of dichlorobenzene cannot meet the demand of the market

There are roughly methods for people to obtain dichlorobenzene: 1) It is separated from the heavy component by-products produced by chlorinated benzene, but the quantity is extremely limited; 2) Using ferric chloride as a catalyst, chlorinated benzene and chlorine gas are used as raw materials to further in-depth Dichlorobenzene is obtained by chlorination, and chlorobenzene is obtained after benzene chlorination, water washing, alkali washing, and rectification, which will greatly increase the raw material cost of dichlorobenzene, and the speed of generating dichlorobenzene by chlorination of chlorobenzene Also very slow, equipment investment is bigger; 3) generally all adopt batch reactor, in the benzene that contains ferric trichloride, feed chlorine continuously and make dichlorobenzene, this kind method scale is small, and product composition is unstable, and by-product The amount of polychlorobenzene increases, which is not conducive to post-treatment; 4) column continuous reactor, benzene, ferric chloride catalyst and chlorine are added continuously, due to the lack of necessary stirring and no suitable catalyst, the production capacity is low, and the production capacity is low. Neighborhood imbalance, large equipment investment, not suitable for large-scale production

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