Process for preparing 2-cyan-4-nitroaniline through micro-channel reaction

Abstract

The invention provides a process for preparing 2-cyan-4-nitroaniline through a micro-channel reaction. The process comprises the following steps: S1, dissolving chlorobenzonitrile into dichloroethaneso as to obtain a first material of the micro-channel reaction, taking a mixture of concentrated sulfuric acid and concentrated nitric acid as a second material of the micro-channel reaction, feedingthe first material and the second material into a micro-channel reactor simultaneously in a specific flow ratio, performing operation such as elutriation and filtering on the discharged material so asto obtain a nitration intermediate, namely 2-chloro-5-nitrobenzonitrile, and performing GC (gas chromatography) detection on the product; S2, dissolving the intermediate prepared in the step S1 intoa specific solvent, and transferring the intermediate into a high-pressure reaction kettle for later use; S3, introducing ammonia gas into the high-pressure reaction kettle quantitatively, and performing an ammoniation reaction; and S4, filtering the mixture in the step S3, performing thermal backflow pulping, and performing drying, so as to obtain a finished product, namely 2-cyan-4-nitroaniline.By adopting the process, the danger that splashing, explosion and the like of materials can be easily resulted from heavy heat release in a nitration reaction can be greatly reduced, and in addition,the amount of waste sulfuric acid can be small, and the energy consumption is low.

Description

technical field [0001] The invention generally relates to the technical field of fine chemicals, and in particular relates to a process for preparing 2-cyano-4-nitroaniline by microchannel reaction. Background technique [0002] 2-cyano-4-nitroaniline is an important intermediate in the synthesis of disperse dyes, used for the synthesis of 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. Due to the need to use nitration and ammonification reactions in the preparation, the traditional nitration reaction has the disadvantages of low efficiency and large amount of waste acid, and the traditional ammonification reaction has the disadvantages of high solvent boiling point, difficult recovery, large amount of ammonia consumption, high reaction pressure, etc., which is relatively dangerous. Big. Contents of the invention [0003] The object of the present inventio...

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Problems solved by technology

[0003] The object of the present invention is to provide a kind of technology that utilizes microchannel reaction to prepare 2-cyano-4-nitroaniline, and this technology is different from traditional kettle type mixed acid nitration reaction, and this technology uses o-chlorobenzonitrile, concentrated nitric acid etc. as The main raw material, using dichloroethane as a solvent, firstly prepares the intermediate 2-chloro-5-nitrobenzonitrile through nitration reaction in a microchannel reactor. This reaction can be carried out at room temperature, which overcomes the traditional In the process, the energy consumption of nitrification reaction at low temperature is too large, and the waste acid is produced in a large amount, and the process is dangerous.

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