Method for synthesizing 4-chloro-2, 5-dimethoxynitrobenzene by using microreactor

Abstract

The invention relates to a method for synthesizing 4-chloro-2, 3, 5-tetramethylpiperidine by using a microreactor. According to the method, intermediate 2, 5-dimethoxychlorobenzene of 4-chloro-2, 5-dimethoxynitrobenzene and nitric acid are used as raw materials, 4-chloro-2, 5-dimethoxynitrobenzene is synthesized through the microreactor, in the reaction process, the mass fraction of nitric acid is50%-95%, and the mass fraction of a 2, 5-dimethoxychlorobenzene solution is 15%-50%; the feeding molar ratio of nitric acid to 2, 5-dimethoxychlorobenzene is (1.0-1.5): 1, the reaction temperature is50-85 DEG C, the feeding temperature is not higher than 50 DEG C, and the reaction retention time is 30-120 seconds. According to the method, on one hand, the process conditions such as the materialratio and the reaction temperature are accurately controlled, the dosage of nitric acid is reduced, the method is environmentally friendly, the conversion rate of 2, 5-dimethoxychlorobenzene reaches 99.98%, and the yield of 4-chloro-2, 5-dimethoxynitrobenzene reaches 99.5% or above; on the other hand, the key problems of corrosivity of nitric acid, difficulty in controlling the reaction temperature, poor mass and heat transfer effect, poor safety and the like in the conventional synthesis process are solved, and the reaction risk is low; strong operability.

Description

technical field [0001] The invention belongs to the technical field of preparing 4-chloro-2,5-dimethoxynitrobenzene, and relates to a method for synthesizing 4-chloro-2,5-dimethoxynitrobenzene by using a microreactor. Background technique [0002] The chemical formula of 4-chloro-2,5-dimethoxynitrobenzene is C 8 h 8 ClNO 4 , whose structural formula is shown in Formula I, is an important intermediate for the synthesis of high-grade azo pigments C.I.P.Y.83 and C.I.P.R.146. These two yellow and red organic pigments are mainly used for the coloring of high-grade inks, plastics and rubber, and have excellent applicability. [0003] The traditional chemical synthesis method of 5-chloro-2,5-dimethoxynitrobenzene mostly uses hydroquinone as a raw material, which is prepared through methylation, chlorination and nitration (Sun Jiyou, 2,5-dimethoxy Research on the synthesis of base-4-chloronitrobenzene, Chemical Industry and Engineering, 1998, 001, 015, 41~45, 53), wherein, the n...

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Problems solved by technology

[0009] The present invention is carried out in order to solve the above-mentioned problems, adopts microreactor as the reactor of 4-chloro-2,5-dimethoxynitrobenzene nitration process, overcomes traditional nitration reaction intermittent reaction in tank reactor, The production efficiency is low, the heat release of the reaction is not easy to control, the liquid holding capacity of the reaction is large, and the reaction risk is high, and the reaction conditions are explored

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