Preparation method of 6-chloro-2,4-dinitroaniline

Abstract

The invention discloses a preparation method of 6-chloro-2, 4-dinitroaniline. The preparation method comprises the following steps: a, dispersing 2,4-dinitroaniline in hydrochloric acid and a catalyst, and carrying out pulping, wherein the mass fraction of the hydrochloric acid is 1-6 wt%; b, introducing chlorine gas into a pulping material obtained in the step a and carrying out a chlorination reaction; c, adding a sodium chlorate solution into a reaction solution obtained in the step b, and continuing the chlorination reaction, wherein the mass fraction of the sodium chlorate solution is 20%-40%; d, filtering a reaction liquid obtained in the step c, washing a filter cake by a washing device until the pH value of the filter cake is 6.0-7.0, returning mother liquor to the step a to be circularly and indiscriminately used as hydrochloric acid and the catalyst, and discharging the mother liquor into a wastewater treatment system until the concentration of sodium chloride in the mother liquor is saturated; and e, putting the filter cake obtained in the step d into an air flow drying machine for drying to obtain the 2,4-dinitro-6-chloroaniline. The method has the advantages of small overall water consumption and good cleaning effect.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a preparation method of 6-chloro-2,4-dinitroaniline. Background technique [0002] 6-Chloro-2,4-dinitroaniline, also known as 2-chloro-4,6-dinitroaniline, CAS No. 3531-19-9, is an important dye intermediate, as a diazo group It is mainly used for the synthesis of disperse blue 270, 264, 259, 125 and 130, etc., and the disperse dyes made from it are widely used in the printing and dyeing industry of synthetic fibers. [0003] The concentration of hydrochloric acid used in the existing industrial production is high, the cost is high, and the mother liquor can be circulated in a small number of batches, and the acid content of the mother liquor wastewater is high. In addition, the acid content in the filter cake is also high, and the water consumption during washing is large. Reduced waste water discharge; the existing filter cake cleaning method is soaking, if a large nu...

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Problems solved by technology

[0003] The concentration of hydrochloric acid used in the existing industrial production is high, the cost is high, and the mother liquor can be circulated in a small number of batches, and the acid content of the mother liquor wastewater is high. In addition, the acid content in the filter cake is also high, and the water consumption during washing is large, which also increases Reduced waste water discharge; the existing filter cake cleaning method is immersion washing, if a large number of filter cakes are cleaned at the same time, the cleaning efficiency is low, the filter cakes are easy to contaminate each other, and the water consumption is large; if the filter cakes are divided into multiple parts for separate cleaning, Intermittent opening and closing equipment is required to load and unload materials, which affects the service life of the equipment and is time-consuming and laborious. In this way, if it is necessary to improve the cleaning efficiency, multiple cleaning equipment will be purchased, which will increase the production cost and is not convenient for manual operation.

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