The synthetic method of cyhalofop-ethyl

Abstract

The invention relates to the field of chemical industry, and discloses a cyhalofop butyl synthetic method. The method comprises the following steps: 1) R-2-(4-hydroxyphenoxy)propionic acid and a catalyst are dissolved in an organic solvent to obtain a mixed solution M1; 2) slowly adding an acid binding agent in the solution M1 until no gas is generated to obtain a mixed solution M2; 3) adding bromobutane in the solution M2, reacting the materials to generate an intermediate R-2-(4-hydroxyphenoxy)butyl propionate at the temperature of 85-95 DEG C; and 4) keeping the temperature in the step 3), and adding 3,4-difluorobenzonitrile and reacting to generate the target product cyhalofop butyl. Compared with the prior art, a whole process is completed in a same reaction container, only steps (3) and (4) in the reaction keep the temperature at 85-95 DEG C, The subsequent raw materials can be directly added, the process is simple, the operation is easy, the reaction rate is high, the synthesis efficiency is high, and the yield is high.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a method for synthesizing cyhalofop-ethyl. Background technique [0002] There are two main methods for producing cyhalofop-methyl from 3,4 difluorobenzonitrile. One method is: 3,4 difluorobenzonitrile first reacts with hydroquinone to synthesize the intermediate 4-(4-cyano -2-fluorophenoxy) phenol, then react with (S)-2-(4-methylbenzenesulfonyloxy) butyl propionate to obtain cyhalofop-methyl; hydroquinone is easy to generate in this method Two substitution impurities have seriously affected the product yield. Another method is: 3,4 difluorobenzonitrile is first reacted with R-2-(4-hydroxyphenoxy)ethyl propionate and then reacted with sodium hydroxide to obtain an intermediate, which is then reacted with butanol to obtain Cyhalofop-ethyl; this method has a long reaction route, inconvenient operation and low yield. [0003] The application publication number is CN105601538A, an...

AI Technical Summary

Problems solved by technology

[0002] There are two main methods for producing cyhalofop-methyl from 3,4 difluorobenzonitrile. One method is: 3,4 difluorobenzonitrile first reacts with hydroquinone to synthesize the intermediate 4-(4-cyano -2-fluorophenoxy) phenol, then react with (S)-2-(4-methylbenzenesulfonyloxy) butyl propionate to obtain cyhalofop-methyl; hydroquinone is easy to generate in this method Disubstituted impurities seriously affect the product yield

[0007] The applicant has found that the following disadvantages exist in the above etherification reaction process: the first intermediate produced after the heat preservation reaction is potassium salt (take the acid-binding agent as potassium carbonate as an example), and the potassium salt needs to be dissolved in water and then acid is added to adjust the pH to 3 to 5 to generate the required intermediate (R)-2-[(4-(2-fluoro-4 nitrile)-phenoxy group)]-propionic acid, the process is more loaded down with trivial details; in the above-mentioned dehydration esterification reaction process There are the following disadvantages: the intermediate (R)-2-[(4-(2-fluoro-4 nitrile)-phenoxy group)]-propionic acid needs to be obtained through filtration, and then added to the reaction vessel with n-butanol A reversible esterification reaction occurs between them, the operation is cumbersome, and the reaction product not only generates ester but also generates water. The product water must be removed to promote the esterification reaction to the right, otherwise the esterification reaction will reverse after a period of time. carry out, hinder the process of esterification, and the process of dehydration is relatively slow, which undoubtedly leads to the low efficiency of the preparation of the whole cyhalofop-ethyl

Images