Chemical synthesis process of 4-chloro-2-fluoro nitrobenzene

Abstract

The present invention is a chemical synthesis process of 4-chloro-2-fluoro nitrobenzene. The synthesis process includes diazotization of 5-chloro-2-nitro benzene as initial raw material, reaction with aqueous solution of phosphofluoric acid to produce corresponding diazotized salt, and then thermal decomposition to prepare 4-chloro-2-fluoro nitrobenzene. The process has the advantages of easy to obtain raw material, mild reaction condition, and high product purity.

Description

Technical field: [0001] The present invention relates to a new method for synthesizing 4-chloro-2-fluoronitrobenzene. The method uses 5-chloro-2-nitroaniline as a starting material to prepare 4-chloro-2-fluoronitrobenzene. And 5-chloro-2-nitroaniline can be prepared conveniently by known methods using 3-chloroaniline as a starting material. Background technique: [0002] 4-Chloro-2-fluoronitrobenzene is an important intermediate in the synthesis of low-toxicity, broad-spectrum, ultra-efficient herbicide fluthiazol and other agricultural conventions. Most of the existing synthetic methods use 2,4-dichloronitrobenzene as the starting material to prepare 4-chloro-2-fluoronitrobenzene through halogen displacement reaction. For example, the method reported by British Patent (GB 1514082) is to allow 2,4-dichloronitrobenzene to react with dry potassium fluoride in a sulfolane medium at 240°C for 6-33 hours to obtain 4-chloro-2-fluoronitrobenzene Mixtures of benzene, 2-chloro-4-f...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the starting material 3,4-dinitrochlorobenzene is not easy to get, the price is higher, and the purity of industrial products is only 90%.