Environment-friendly process for quizalofop-p-ethyl production

Abstract

The invention relates to an environment-friendly process for quizalofop-p-ethyl production. The environment-friendly process is characterized by comprising the following steps: firstly enabling hydroquinone to react with sodium hydroxide to prepare sodium salt of the hydroquinone, then reacting with 2,6-dichloroquinoxaline to obtain 4-(6-chloro-2-quinoxalinyloxy) and reacting with ethyl lactate p-toluenesulfonate to obtain the quizalofop-p-ethyl; then performing alkaline hydrolysis and acidification on produced quizalofop-p-ethyl butter and recovering 6-chloro-2-quinoxalinone. The synthetic process has the advantages that as the reaction and the post-treatment are performed in an organic solvent, the alkalinity of a reaction system is reduced, the defect that impurities are easy to generate due to too strong aqueous phase reaction alkalinity is overcome, and the hydrolysis of 2,6-dichloroquinoxaline as a raw material is reduced, so that the content of 4-(6-chloro-2-quinoxalineoxy) phenol reaches 98 percent or above, and the yield reaches 92 percent or above; 6-chloro-2-hydroxyquinoxaline in the quizalofop-p-ethyl butter is recovered, so that the solid waste discharge amount is reduced, the environment is protected, and the intermediate cost of the quizalofop-p-ethyl is reduced.

Description

technical field [0001] The invention relates to the technical field of pesticide synthesis, in particular to an environment-friendly process for producing quizalofop-p-ethyl. Background technique [0002] Quizalofop-ethyl is a post-emergence selective herbicide developed by Nissan Chemical Industry Co., Ltd., Japan. It shows strong killing effect on annual and perennial grass weeds, and is safe for broad-leaved crops. It can be widely used in cotton, rapeseed, The control of gramineous weeds in crops such as peanuts, soybeans and various broad-leaved vegetables, so it has broad prospects for the synthesis of original drugs and the processing of preparations. [0003] At present, there are two synthetic routes for quizalofop-p-ethyl, one is to use 2,6-dichloroquinoxaline as a raw material, the reaction shown in equation 1 occurs, and the direct or re-esterification reaction obtains quizalofop-p-p-p, the other The route is to prepare 4-(6-chloro-2-quinoxalinyloxy)phenol, whic...

AI Technical Summary

Problems solved by technology

[0009] Up to now, in the prior art, the aqueous phase etherification reaction involving 2,6-dichloroquinoxaline and potassium hydroxide has been mainly introduced. The reaction system is extremely alkaline, and active chlorine in 2,6-dichloroquinoxaline is prone to Hydrolysis affects the yield of etherification reaction. Secondly, due to the high concentration of alkali, two molecules of 2,6-dichloroquinoxaline and one molecule of hydroquinone are generated with more impurities, and the content of etherification products is lower;

[0010] The etherification reaction of 2,6-dichloroquinoxaline and sodium hydroxide in a mixed solvent of toluene and DMF, the reaction uses DMF, which has a strong solubility for the product, and the ratio of 2,6-dichloroquinoxaline to the amount of alkali About 1:5, there are too many bis-ether impurities. In addition, ice water is required for post-treatment. The steps are complicated. The ice water will mix with the solvent and it is difficult to handle, which will affect the solvent recovery.

[0011] The solid quizalofop-pyl-quine butter produced during the crystallization of the quizalofop-p-p-ethyl in the preparation process of the existing technology after the solvent is recovered, contains more quizalofop-pyl-quine in the butter, and also contains some impurities generated during the synthesis process. seriously pollute the environment

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