Preparation method for 2-chloro-4-nitroaniline

A technology of p-nitroaniline and o-chlorine, which is applied in the preparation of amino compounds, the preparation of organic compounds, chemical instruments and methods, etc., can solve problems such as operational danger, environmental pollution, and a large amount of waste water, achieve high quality and reduce equipment costs. and operating costs, the effect of reducing the cost of raw materials

Active Publication Date: 2009-01-14
苏州市罗森助剂有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Adopt the preparation method of high-pressure ammonolysis reaction, although the quality of the o-chloro-p-nitroaniline of preparation is better, but equipment investment is huge, and operation is dangerous, and because it generates by-product NH 4 Cl will produce a large amount of waste water and pollute the environment
And in the method for preparing o-chloro-p-nitroaniline by dripping sodium hypochlorite solution, at first will make sodium hypochlorite solution, be about to pass chlorine in the sodium hydroxide solution, not only need investment equipment, also can cause a large amount of waste acid mother liquors
In addition, in the production process of sodium hypochlorite, it is necessary to control the production quality of sodium hypochlorite, that is, available chlorine and free alkali, and the process is very complicated; and because sodium hypochlorite solution reacts with p-nitroaniline, sodium chloride will be produced, so that The mother liquor can not be recycled and the quality and appearance of o-chloro-p-nitroaniline are affected, resulting in poor appearance and low content of o-chloro-p-nitroaniline

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0014] According to the preparation method of the o-chloro-p-nitroaniline of the present embodiment is as follows:

[0015] First, add 20g of p-nitroaniline into 200g of 10% HCl, heat to dissolve it all, then cool the solution to -10~0°C, and use 0.49m 3 Chlorine gas is introduced per hour, and the chlorine gas flow time is controlled at about 7 hours. After the chlorine gas flow is completed, continue to heat and stir at -10~0°C for 1 hour, and then carry out suction filtration at 0°C. The mother liquor is reserved for the next batch. Wash with water until neutral and suck dry to obtain 24.7 g of dry product, which is the said o-chloro-p-nitroaniline. The chromatographic content of o-chloro-p-nitroaniline is 96.3%, and the calculated molar yield is 98.2%.

example 2

[0017] First, add 20g of p-nitroaniline into 200g of 8% HCl, heat to dissolve it all, then cool the solution to -10~0°C, and use 0.49m 3 Chlorine gas is introduced per hour, and the chlorine gas flow time is controlled at about 7 hours. After the chlorine gas flow is completed, continue to heat and stir at -10~0°C for 1 hour, and then carry out suction filtration at 0°C. The mother liquor is reserved for the next batch. Wash with water until neutral and suck dry to obtain 24.7 g of dry product, which is the said o-chloro-p-nitroaniline. The chromatographic content of o-chloro-p-nitroaniline is 95.8%, and the calculated molar yield is 98.2%.

example 3

[0019] Except that dilute hydrochloric acid concentration is used 11%, all the other are identical with example 1, make o-chloro-p-nitroaniline 24.5g, chromatographic content 94.8%, calculated molar yield is 97.4%.

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Abstract

The invention relates to a preparation method of o-chloro-p-nitroaniline, which takes p-nitroaniline as a raw material, and prepares the o-chloro-p-nitroaniline by directly inputting chlorine gas for implementing the chlorination reaction in a diluted hydrochloric acid medium with a temperature of between -20 and 10 DEG C, wherein, the p-nitroaniline and the input chlorine gas are present in a molar ratio of 1:1-1.1. The preparation method can prepare the o-chloro-p-nitroaniline with best quality, and has advantages of simple process, high yield, low production cost and non wastewater discharge.

Description

technical field [0001] The invention relates to a preparation method of o-chloro-p-nitroaniline. Background technique [0002] O-chloro-p-nitroaniline is an important intermediate of dyes and pigments, and it can also be used to synthesize busnail pesticides. At present, there are two main preparation methods for o-chloro-p-nitroaniline, one is formed by high-pressure ammonolysis reaction of 3,4-dichloronitrobenzene in concentrated ammonia water medium; the other is p-nitroaniline In dilute hydrochloric acid medium, it is prepared by slowly adding sodium hypochlorite solution dropwise under low temperature conditions. Adopt the preparation method of high-pressure ammonolysis reaction, although the quality of the o-chloro-p-nitroaniline of preparation is better, but equipment investment is huge, and operation is dangerous, and because it generates by-product NH 4 Cl will produce a large amount of waste water and pollute the environment. And in the method for preparing o-ch...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/74C07C211/52
Inventor 李根荣徐新连裘雪根
Owner 苏州市罗森助剂有限公司
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