Synthetic method of 2-methyl-4-chlorophenoxyacetic acid

Abstract

The invention discloses a synthetic method of 2-methyl-4-chlorophenoxyacetic acid and relates to the technical field of organic synthesis. According to the method, o-methylphenol used as a raw material reacts with sodium chloroacetate under the action of sodium methylate; then, a reaction product is neutralized with hydrochloric acid to obtain an intermediate 2-methylphenoxyacetic acid; and finally, the intermediate is subjected to chlorination with sulphone chloride to obtain a target product 2-methyl-4-chlorophenoxyacetic acid. According to the invention, sodium methylate replaces sodium hydroxide to undergo neutralization. The neutralization reaction is relatively thorough, and there are few by-products, thus being beneficial to raise content and yield of the product. In addition, sulphone chloride is used for chlorination. The reaction is a water-free reaction, and generation of lots of phenolic wastewater is minimized. Thus, the reaction meets requirements of modern green pesticides. In addition, reaction temperature is relatively low, thus reducing energy consumption. In comparison with original technologies, the reaction technology has obvious advantages of high yield, less ''three wastes (waste gas, wastewater and industrial residue)'' and low energy consumption.

Description

Technical field: [0001] The invention relates to the technical field of organic synthesis, in particular to a synthesis method of 2-methyl-4-chlorophenoxyacetic acid. Background technique: [0002] There are many types of herbicides currently available on the market, and phenoxyacetic acid herbicides account for an important one. Due to the different substituents and substituent positions on the benzene ring, and the different numbers of carbon atoms of the carboxylic acid, different phenoxycarboxylic acid herbicides are formed. 2-Methyl-4-chlorophenoxyacetic acid is a hormone-type systemic phenoxycarboxylic acid herbicide developed and promoted by Imperial Chemical Industrirs in 1945. It has strong physiological activity on plants and is easy for roots and leaves. surface absorption and conduction. At low concentration, it can stimulate the growth of crops, prevent flower and fruit drop, form seedless fruit, promote fruit ripening and rooting of cuttings, etc.; at high co...

AI Technical Summary

Problems solved by technology

Therefore, the global research on 2-methyl-4-chlorophenoxyacetic acid has not stopped so far.

[0003] The synthetic route of 2-methyl-4-chlorophenoxyacetic acid mainly adopts neutralization-condensation-chlorination, and most manufacturers use sodium hydroxide to neutralize and chlorine to chlorinate, but there is no neutralization in sodium hydroxide. The shortcomings of thoroughness and few by-products reduce the content and yield of the product; and the use of chlorine chlorination will produce a large amount of difficult-to-treat phenol-containing wastewater

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