A kind of preparation method of p-chlorobenzaldehyde

Abstract

The invention discloses a preparation method of p-chlorobenzaldehyde, which uses p-chlorotoluene as a raw material to undergo a substitution reaction with chlorine under the action of a catalyst to obtain a mixture of p-chlorobenzyl chloride and p-chlorobenzylidene dichloride. The mixture of p-chlorobenzyl chloride and p-chlorobenzylidene dichloride undergoes hydrolysis reaction and air catalytic oxidation reaction under the action of a catalyst to obtain p-chlorobenzaldehyde. The present invention reduces the reaction temperature of the substitution reaction through the action of the catalyst, improves the selectivity of the substitution reaction, adopts the combination of the hydrolysis reaction and the air catalytic oxidation reaction to improve the yield of p-chlorobenzaldehyde, and reduces the yield of p-chlorobenzaldehyde through the mechanical application of the catalyst. The amount of waste water from the hydrolysis reaction.

Description

technical field [0001] The invention relates to the field of fine organic chemical synthesis, in particular to a method for preparing a fine chemical intermediate p-chlorobenzaldehyde. Background technique [0002] p-Chlorobenzaldehyde (4-chlorobenzaldehyde), English name: p-Chlorobenzaldehyde (4-Chlorobenzaldehyde). 4-Chlorobenzaldehyde is an important fine chemical intermediate, which is widely used in pesticides, medicines, dyes and other organic synthesis. In terms of pesticides, it is mainly used to synthesize the fungicide tebuconazole and the insecticide chlorfenapyr. In medicine, it is mainly used in the synthesis of sedatives such as Fenalu. In terms of dyes, it is mainly used in the synthesis of acid brilliant blue 6B and so on. [0003] Taking p-chlorotoluene as a raw material through substitution and hydrolysis to prepare p-chlorobenzaldehyde mainly contains the following three methods: 1. P-chlorotoluene is substituted with chlorine under ultraviolet light to...

AI Technical Summary

Problems solved by technology

[0020] 1. The substitution reaction conditions are harsh and the selectivity is low;

[0021] 2. The yield of hydrolysis reaction is low and the cost is high;

[0022] 3. The amount of hydrolyzed wastewater is large and the treatment is difficult

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