Method for synthesizing 2-(5-fluoro-1, 5 dinitro-phenoxy) acetate

Abstract

The invention discloses a method for synthesizing 2-(5-fluoro-1, 5 dinitro-phenoxy) acetate. 2, 4-dichloronitrobenzene serves as a raw material, nitration reaction is performed to obtain 2, 4-dichloro-1, 5-dinitrobenzene, the quantity of fluorinating agents and reaction conditions are controlled in aprotic polar solvents DMF, fluorination reaction with potassium fluoride is performed to obtain 2-fluoro-4-chloro-1, 5-dinitrobenzene, and the 2-fluoro-4-chloro-1, 5-dinitrobenzene is polarized in the etherified aprotic polar solvents DMF and subjected to etherification reaction with hydroxy acetate under the action of acid-binding agents and catalysts to obtain the 2-(5-fluoro-1, 5 dinitro-phenoxy) acetate. In addition, raw materials are inexpensive and easy to obtain, operation is simple andconvenient, technological conditions of reaction in all steps are mild, the method is high in safety and short in reaction time, and industrial production can be popularized.

Description

technical field [0001] The invention relates to the technical field of herbicide production and preparation, in particular to a method for synthesizing 2-(5-fluoro-1,5-dinitrophenoxy)acetate. Background technique [0002] 2-(5-fluoro-2,4-dinitrophenoxy) acetate is a kind of pesticide intermediate, which can synthesize the herbicide flumechlor, which is protoporphyrinogen oxidase ( PPO) inhibitors are used to control weeds and broad-leaved weeds on soybeans, cotton, grapes and many other crops. The chemical structure of 2-(5-fluoro-2,4-dinitrophenoxy)acetate is as follows. Its chemical structural formula is as follows: [0003] [0004] Among the various synthetic techniques that have been published so far, there are m-dichlorobenzene as raw materials, and the precursor 2-(5-fluoro-2,4-dinitrophenoxy) is obtained through nitration, fluorination, etherification and other steps. Acetate and m-dichlorobenzene add two nitro groups at the same time, there are many by-products...

AI Technical Summary

Problems solved by technology

[0004] Among the various synthetic techniques that have been published so far, there are m-dichlorobenzene as raw materials, and the precursor 2-(5-fluoro-2,4-dinitrophenoxy) is obtained through nitration, fluorination, etherification and other steps. Acetate and m-dichlorobenzene add two nitro groups at the same time, there are many by-products, and the reaction conditions are severe and the safety factor is low. When dichlorofluorination to difluoride, there are also impurities of one chlorine and one fluorine, and the amount of post-treatment tar is large. The loss of the product is large, and etherification will produce impurities where both fluorines are etherified

There is m-fluorophenol as the starting material, although the reaction route is not very long, but the raw material is rare and expensive, the nitration reaction conditions are severe, the ether bond is easy to break, the impurities are high, and the product yield is low

With 2,4-difluoronitrobenzene as the raw material, the last step to achieve 2-(5-fluoro-2,4-dinitrophenoxy) acetate, after hydrolysis, etherification, reduction, nitration, Reduction, although the raw materials are easy to obtain in this route, but the route is long, the impurities are high, and hydrogenation is required twice at the same time, the cost is increased, and the operation is cumbersome

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