Industrial production method of 2,6-difluoroaniline

Abstract

The invention discloses an industrial production method of 2,6-difluoroaniline, wherein the industrial production method comprises the following steps: S1, preparation of a solution: mixing a sodium hydroxide aqueous solution and 2,6-difluorobenzamide to obtain a solution 1, and taking a sodium hypochlorite aqueous solution as a solution 2; S2, equipment building: connecting reaction kettles 1 and2 with a reaction kettle 3 through diaphragm pumps 1 and 2 respectively, and connecting the reaction kettle 3 with a reaction kettle 4 through an overflow pipe; S3, degradation reaction: simultaneously pumping the solution 1 and the solution 2 into the reaction kettle 3 by using the diaphragm pumps 1 and 2, and enabling a reaction liquid to flow out of an overflow pipe to the reaction kettle 4; S4, primary distillation: evaporating the product 2,6-difluoroaniline to a receiving kettle along with water vapor in the overflow pipe; and S5, rectifying of a crude product: rectifying after a liquidin the receiving kettle is layered. The CSTR mode is adopted to control the addition amount and time of the reaction liquid, so that the reaction is more controllable, and the problems of product heating damage and easy material flushing in the production process caused by violent material heat release in traditional kettle type reaction are avoided.

Description

technical field [0001] The invention relates to the field of preparation methods of pesticides, in particular to an industrial production method of 2,6-difluoroaniline. Background technique [0002] 2,6-Difluoroaniline, CAS: 5509-65-9, colorless or pale yellow liquid, boiling point 144°C-148°C. It is mainly used as a key intermediate for the synthesis of new pesticides, insecticides and herbicides, and can also be used to prepare liquid crystal materials for fuel cells and electronics industries. 2,6-Difluoroaniline is a key intermediate for the synthesis of new benzoylurea pesticides, which can be made into various insecticides and herbicides such as hexaflumuron, fluflubenzuron, diflubenuron, and fenfluranuron . This series of pesticides has the effect of preventing larvae from moulting and growing into adults, so that their dosage is small, their toxicity is low, and they have no drug resistance. They are new types of pesticides with high efficiency and low toxicity. T...

AI Technical Summary

Problems solved by technology

A lot of practical experience shows that there will be an exothermic and gas-producing stage during the heating process of the Hofmann amide degradation reaction. This process will cause a short-term intense exothermic process, which will cause the product to be destroyed by heat, and impurities will be generated to reduce the purity of the product.

At the same time, short-term intense heat release may also lead to material loss during the production process.

[0004] Aiming at the problem of severe exothermic reaction in the traditional Hofmann degradation reaction process, which leads to the thermal damage of the product and the formation of impurities to reduce product purity and easy flushing in the production process, the present invention proposes a CSTR mode for the production and preparation of 2,6-difluoroaniline Methods