Synthesis method of paranitroaniline

Abstract

The invention discloses a continuous synthesis method of paranitroaniline. The continuous synthesis method comprises the following steps: 1) preparing ammonia water by using an ammonia water preparation unit, respectively and continuously inputting the prepared ammonia water and molten p-nitrochlorobenzene into a feeding and mixing unit, carrying out preheating to a reaction temperature, and then,mixing the materials; 2) making the mixed materials flow into a tubular reactor for a reaction, then, making the reacted materials flow into a shunt circulation unit, and dividing the materials intoa circulating material and an outflow material according to a certain recycle; and 3) returning the circulating material to the feeding and mixing unit, and sequentially carrying out continuous onlinemixing on the circulating material as well as the ammonia water and the p-nitrochlorobenzene preheated to the reaction temperature; and cooling the outflow material to crystallize to obtain paranitroaniline with the yield reaching up to 99% or above. The method disclosed by the invention simultaneously has the advantages such as high production efficiency, good safety, low equipment material requirement, flexible and easily-controlled production process and low comprehensive cost and meets the requirements for safety, greenness and high efficiency.

Description

technical field [0001] The invention belongs to the field of fine chemicals, and in particular relates to a synthesis method of p-nitroaniline. Background technique [0002] p-Nitroaniline is an extremely important intermediate in organic synthesis in the fields of dyes, pesticides, antioxidants, etc. It can directly synthesize o-chloro-p-nitroaniline, 2,6-dichloro-p-nitroaniline, p-phenylene Amines, etc., are further used in the manufacture of azo dyes, such as direct dark green B, acid medium brown G, acid black 10B, etc. [0003] At present, the domestic production method of p-nitroaniline is mainly the amination method of p-nitrochlorobenzene. p-Nitrochlorobenzene and concentrated ammonia water are reacted in a stirred tank at 140-180°C, 3.7-5.5MPa, and a large excess of ammonia water for 15-20 hours, and crystallized and filtered to obtain p-nitroaniline. The process mainly has problems such as low production efficiency, unstable product quality, and poor reliability ...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a safe, efficient and green synthetic method of p-nitroaniline, which solves the problems of low production efficiency, unstable product quality, and poor reliability of equipment amplification in the existing p-nitroaniline preparation process. question

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