Method for preparing p-chloro-o-nitroacetoacetanilide by using packed bed reactor

Abstract

The invention belongs to the field of chemical synthesis, and relates to a method for preparing p-chloro-o-nitroacetoacetanilide by using a packed bed reactor, which comprises the following specific steps that: p-chloro-o-nitroaniline is dissolved in toluene, and diketene is added into a reaction system and is stirred well for later use; the reaction liquid is pumped into a packed bed reactor filled with a solid acid catalyst from the upper end through a pump at a constant flow speed, and the reaction liquid flows out from the bottom and enters a reaction liquid collector; and after the reaction liquid is detected to be qualified, most of the solvent is removed under negative pressure, cooling and crystallizing are carried out, and suction filtration and drying are carried out to obtain the product. Compared with the prior art, the method has the advantages that an acid cation exchange resin catalyst is used, so that the catalyst can be repeatedly used, and continuous production is achieved; and meanwhile, the catalyst is large in specific surface area and high in catalytic activity, so that the reaction period is shortened, impurity control is facilitated, the product purity is high (98%), and the yield is high (98%).

Description

technical field [0001] The invention relates to the field of chemical synthesis, and specifically provides a method for preparing p-chloro-o-nitroacetoacetanilide using a packed bed reactor. Background technique [0002] Quizalofop-ethyl is also called Jinghecaogram and Xianhoe. It is an improved product after removing the inactive optical isomer (L-body) during the synthesis of quizalofop. Quizalofop-ethyl is a highly selective new dry field stem and leaf treatment agent, which is highly selective between grass weeds and dicotyledonous crops, and has a good control effect on grass weeds in broad-leaved crop fields . [0003] p-chloro-o-nitroacetoacetanilide, Chinese aliases: acetylacetyl-p-chloro-o-nitroaniline, N-(4-chloro-2-nitrophenyl)-3-oxo-butyramide. P-chloro-o-nitroacetoacetanilide is an intermediate for the synthesis of quizalofop-p-ethyl. At present, the main raw materials for the synthesis of p-chloro-o-nitroacetoacetanilide are p-chloro-o-nitroacetoanilide and...

AI Technical Summary

Problems solved by technology

[0007] The more mature route of synthesizing p-chloro-o-nitroacetoacetanilide is mainly: to prepare p-chloro-o-nitroacetoacetanilide with p-chloro-o-nitroaniline and diketene under heating conditions, using a one-pot reaction method. In this method, one On the one hand, diketene is prone to self-polymerization reaction in an alkaline environment, which requires high workshop equipment and reaction conditions, poor production safety, and large impurities in the product, resulting in low product purity; on the other hand, the catalyst is difficult to recycle and reuse. high production cost

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