Synthesis method of 2-cyano-4-nitroaniline

Abstract

The invention provides a synthesis method of 2-cyano-4-nitroaniline. The synthesis method comprises the following steps of: synthesizing 2-cyano-4-nitroaniline; the synthesis method comprises the following steps: a nitration step: 2-chlorobenzonitrile is dissolved in an organic solvent, a nitration reaction is carried out in the presence of mixed acid, a nitration product is obtained, and the nitration product contains 2-chloro-5-nitrobenzonitrile; a mixing step: mixing the nitration product with an inorganic solvent to obtain a mixed product; a separation step: standing and layering the mixed product to obtain an organic phase; ammonia gas and / or ammonia gas are / is introduced into the organic phase, an ammonolysis reaction is carried out, an ammonolysis product is obtained, and the ammonolysis product contains the 2-cyano-4-nitroaniline. According to the synthesis method, a large amount of sulfuric acid can be saved, and the used organic solvent can be recycled after the reaction is finished. Furthermore, the synthetic method disclosed by the invention can ensure that the 2-chloro-5-nitrobenzonitrile does not carry water and the cyano group is not hydrolyzed in the ammonolysis reaction process.

Description

technical field [0001] The invention belongs to the field of synthesis of dye intermediates, in particular to a synthesis method of 2-cyano-4-nitroaniline. Background technique [0002] 2-cyano-4-nitroaniline (C 7 h 5 N 3 o 2 ), which is a light yellow powder at normal temperature and pressure, and is an important dye intermediate. As a diazo component, it can synthesize disperse ruby ​​SE-GFL, disperse bright red S-FL, disperse blue SE-2R, disperse brilliant purple S-R and other high-temperature or medium-temperature disperse dyes; as a raw material, it can synthesize 2-cyanide Base-4-nitro-6-bromoaniline, 3-amino-5-nitro-2,1-benzisothiazole and other important dye intermediates. [0003] At present, the method of industrial production of 2-cyano-4-nitroaniline is to use 2-chlorobenzonitrile (ortho-chlorobenzonitrile for short) as raw material to prepare 2-cyanobenzene through nitration reaction and ammoniation (ammonolysis) reaction. -4-Nitroaniline. It mainly inclu...

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Problems solved by technology

[0007] This technique mainly has the following two disadvantages: (1) in the nitration step, dissolving o-chlorobenzonitrile needs to consume a large amount of sulfuric acid, and the sulfuric acid in the nitration process is both used as a solvent and as a catalyst (to improve the dehydration value of the nitration reaction), and when the amount of sulfuric acid decreases , the material in the reaction system is very thick, and the mass transfer effect is very poor

(2) Ammonolysis step, it is divided into two kinds of chlorobenzene solvent method and ammonia water method, and wherein chlorobenzene solvent method makes the ammonolysis product monochlorobenzene a large amount of residues, is difficult to remove, not environmental protection, general ammonolysis product monochlorobenzene content Tens to hundreds of ppm; the nitration product 2-chloro-5-nitrobenzonitrile of the ammonia method will be hydrolyzed to varying degrees, which will affect the purity of the ammonolysis product

However, the method introduces the extractant chlorinated benzene, which will affect the purity of the ammonolysis product due to the introduction of new substances

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