Method for preparing p-chlorobenzaldehyde

Abstract

The invention discloses a method for preparing p-chlorobenzaldehyde, which comprises the following steps: reacting p-chlorotoluene with chlorine in the presence of an initiator under the irradiation of a mercury lamp at the chlorination temperature of 90-140 DEG C to obtain a p-chlorobenzyl chloride / p-trichlorotoluene mixture; and while controlling the average chlorination degree at 1.4-1.6, carrying out catalytic hydrolysis in a 3-6 wt% nitric acid solution for 6-12 hours to obtain the p-chlorobenzaldehyde. By using the method disclosed by the invention, the next hydrolysis step can be directly carried out without separating the intermediate; and thus, the method is simple in technique and can easily implement industrialized production.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for preparing p-chlorobenzaldehyde. Background technique [0002] p-Chlorobenzaldehyde is an important intermediate of new pesticides, medicines and dyes. In medicine, p-chlorobenzaldehyde can be condensed and cyclized with mercaptopropionic acid to prepare fenalu. In terms of pesticides, p-chlorobenzaldehyde is used to synthesize the herbicide Maidi San, the plant growth regulator paclobutrazol and uniconazole, etc. In terms of dyes, p-chlorobenzaldehyde is used to synthesize acid blue 7BF, acid brilliant blue 6B, etc. [0003] The country that produces p-chlorobenzaldehyde abroad is mainly the United States, which is at the leading level in process technology development and has realized industrial production. Although the research and development of p-chlorobenzaldehyde started late in my country, it has developed rapidly in recent years und...

AI Technical Summary

Problems solved by technology

At present, the total domestic production is less than 1000t / a, which is far from meeting the domestic market demand of more than 2500t / a