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. The target product 2-methyl-4-chlorophenoxyacetic acid is prepared by taking o-methylphenol as a raw material, reacting with sodium chloroacetate udner the effect of sodium bicarbonate; neutralizing by hydrochloric acid to obtain a midbody 2-methyl phenoxyacetic acid; finally, chloridizing the midbody 2-methyl phenoxyacetic acid by chlorine. The method applies sodium bicarbonate to replace sodium hydroxide to carry out neutralization, the neutralization reaction is small in heat release and few in side product; the method is good for improving product content and yield; besides, the chorine is applied to chloridize, and methylbenzene is used as the solvent; the generated acid is used as the neutralizing acid of the next batch, thus the massive phenolic wastewater is reduced, and it can meet the requirement of modern green pesticide; carbon dioxideis discharged from the neutralization reaction, the reaction heat is reduced, and the energy consumption is reduced. Compared with an original technique, the reaction technique has obvious advantagesof high yield, few wastes and low energy consumption.

Description

Technical field: [0001] The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing 2-methyl-4-chlorophenoxyacetic acid. Background technique: [0002] There are many types of herbicides on the market, and phenoxyacetic acid herbicides occupy an important position among them. Due to the different substituents and substitution positions on the benzene ring, and the different number 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 popularized by Imperial Chemical Industrirs in 1945. It has strong physiological activity on plants and is easy to become roots and leaves. Surface absorption and conduction. At low concentrations, it has a growth stimulating effect on crops, which can prevent flower drop, fruit drop, seedless fruit formation, promote fruit maturity and rooting of cu...

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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