New high-yield production process of 6-chloro-2-hydroxyquinoxaline

Abstract

The invention discloses a new high-yield production process of 6-chloro-2-hydroxyquinoxaline. The production process comprises the steps of directly feeding material p-chloro-o-nitroacetoacetanilide into room-temperature alkaline solution, and adopting alkali metal sulfide and acid to instantly generate alkali metal hydrosulfide as reducer in alkaline system. The production process has product content up to above 95%, and total yield up to above 95%.

Description

technical field [0001] The invention belongs to the technical field of pesticides, and in particular relates to a new production process of 6-chloro-2-hydroxyquinoxaline. Background technique [0002] 6-Chloro-2-hydroxyquinoxaline is a key intermediate for the synthesis of the herbicide quizalofop and quizalofop-p-ethyl, and its production method is generally to form sodium salt at room temperature through p-chloro-o-nitroacetoacetanilide , and then the temperature is raised to close the ring to obtain nitrogen oxides, and then to obtain 6-chloro-2-hydroxyquinoxaline through selective reduction. The reducing agent disclosed in patent CN1141034 is alkali metal hydrosulfide and / or alkali metal sulfide. But the yield of preparing 6-chloro-2-hydroxyquinoxaline with the method of this patent (in terms of p-chloro-o-nitroacetoacetanilide yield 85%) is very low. In addition, when p-chloro-o-nitroacetoacetanilide is fed into the lye at 60°C, exothermic phenomenon occurs, and the ...

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Problems solved by technology

However, the yield of 6-chloro-2-hydroxyquinoxaline prepared by the method of this patent (yield 85% based on p-chloro-o-nitroacetoacetanilide) is very low

In addition, when p-chloro-o-nitroacetoacetanilide is added to the lye at 60 ° C, exothermic phenomenon occurs, and the temperature is not easy to control, so it is necessary to feed slowly, prolonging the operation cycle