Preparation process of benzoyl chloride

Abstract

The invention discloses a preparation process of benzoyl chloride. The preparation process comprises the following steps of synthesis of benzotrichloride: carrying out temperature reaction on methylbenzene and chlorine under the catalytic action of a catalyst to synthetize a crude benzotrichloride product; synthesis of the benzoyl chloride: continuously stirring and heating the crude benzotrichloride product and benzoic acid to prepare a crude benzoyl chloride product after adding the catalyst; refining of the benzoyl chloride: carrying out reduced pressure distillation on the crude benzoyl chloride product to prepare a refined benzoyl chloride product; recovering benzoyl chloride raffinate, adding water to the benzoyl chloride raffinate which is subjected to the reduced pressure distillation, heating and stirring to transform the benzoyl chloride contained in the raffinate into the benzoic acid, cooling, then separating out benzoic acid. The preparation process disclosed by the invention is easy to safe to operate, effectively shortens the reaction time, achieves the purity of the prepared benzoyl chloride by 99.5%, reduces the environmental pollution by recycling residues, saves the resources, reduces the cost, meets the requirements of pharmaceutical chemicals and can carry out massive industrial production.

Description

technical field [0001] The invention relates to the preparation and purification of benzoyl chloride and belongs to the field of organic compound synthesis. Background technique [0002] Benzoyl chloride is widely used in the production of monomers in pesticides, medicines and dyes. At present, the preparation of benzoyl chloride mainly uses trichlorotoluene as a raw material, and the production cost is high. [0003] At present, in the process of producing benzoyl chloride, a black viscous residue is produced in the distillation kettle at the later stage of distillation, which contains benzoic acid, benzoyl chloride, benzoic anhydride, catalyst and tar, wherein benzoic acid and benzoic acid are organic matter , because they are mixed in the residue and cannot be completely evaporated, they are generally discharged together with the residue or incinerated, resulting in waste of resources, high cost, and environmental pollution. [0004] The side chain chlorination of toluen...

AI Technical Summary

Problems solved by technology

[0005] Usually, the production of trichlorotoluene adopts the method of photochlorination or one-time addition of solid catalysts. The former is complicated in equipment, and the volume of the equipment is limited, which affects the production capacity. The power consumption of the light source is large, the utilization rate of light energy is low, and the life of the light source is short; The latter has the disadvantages of long reaction time and unstable quality