A kind of 2,4-dinitroaniline preparation method

Abstract

The invention discloses a preparation method of 2,4-dinitroaniline. The preparation method comprises the following steps: a, taking materials: weighing tree materials comprising 2,4-dinitrochlorobenzene, ammonia water and condensed water; b, carrying out preheating: adding the condensed water into a reaction device, and carrying out heating to 50-70 DEG C; c, feeding materials: adding the 2,4-dinitrochlorobenzene into the reaction device, carrying out heating to 80-90 DEG C, and controlling the pressure to be 0.05-01 MPa; d, carrying out amination: slowly dropwise adding the ammonia water intothe reaction device to carry out an amination reaction, and keeping the temperature for 1-3 hours; and e, carrying out centrifuging: centrifugally washing the reaction liquid generated by amination in the step d, and carrying out drying to obtain the 2,4-dinitroaniline. The preparation method has the advantages of fast reaction speed and good reaction effect.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a preparation method of 2,4-dinitroaniline. Background technique [0002] 2,4-Dinitroaniline is an intermediate of disperse dyes, neutral dyes, sulfur dyes, and organic pigments. It is used in the production of dyes such as sulfur dark blue 3R, disperse red B, and disperse violet 2R. It is also used in other organic synthesis, production Pesticide dinitrate powder, etc., as well as toner for printing ink and preparation of preservatives. [0003] The reaction principle of preparing 2,4-dinitroaniline is as follows: 2,4-dinitrochlorobenzene and ammonia water are used as raw materials, which are added to the reaction device to generate 2,4-dinitroaniline through amination reaction. The reaction belongs to the bimolecular nucleophilic substitution reaction. Firstly, the ammonia molecule with the unshared electron pair has a nucleophilic attack on the carbon atom connected...

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Problems solved by technology

[0004] At present, the domestic production of 2,4-dinitroaniline mainly uses the traditional high-temperature and high-pressure method, which has high production safety risks and high energy consumption. Due to the strong volatility of ammonia gas, the volatilized ammonia gas accumulates on the top of the reaction device. Once the reaction device The explosive limit of the ammonia gas concentration in the reactor is 16-25%. If the ammonia gas concentration is too high, it will easily cause an explosion. The ammonia gas after volatilization cannot be effectively used, resulting in an increase in production costs; and ammonia gas is toxic. If it is removed after the reaction Discharge into the air will pollute the air, affect the health of operators, and even endanger their lives

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