Preparation method for 5-chloro-2-nitroaniline

A technology of nitroaniline and dichloronitrobenzene, which is applied in the preparation of nitro compounds, the preparation of hydrogen atoms replaced by amino groups, organic chemistry, etc., can solve the problems of difficult production and low total yield, and reduce environmental pollution, amine High chemical yield and improved cleaning effect

Inactive Publication Date: 2018-07-27
江苏优普生物化学科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Comparing several processes, when m-dichlorobenzene is nitrated into mononitrobenzene, there are few isomers, and 3,5-dichloronitrobenzene and 2,6-dichloronitrobenzene are difficult to produce; while 3-chloronitrobenzene When acetanilide or 3-chloroformanilide is nitrated, 3-chloro-4-nitroacetanilide or 3-chloro-2-nitroacetanilide may be produced. It is also proved from literature and experimental data that m-dichlorobenzene is used as Raw material, the yield of 5-chloro-2-nitroaniline prepared by nitration and amination is the highest, but a large amount of waste acid is produced after nitration, and a large amount of salty wastewater is produced in the post-amination process; 3-chloroaniline is used as raw material for preparation 5-Chloro-2-nitroaniline, the total yield is low, waste acid water is produced after acylation, and a large amount of saline waste water is also produced after nitrification

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Add 100.1g (98.5%, 0.67mol) of m-dichlorobenzene to a 500ml four-necked bottle, start stirring, heat to 40°C in a water bath, and dropwise add 99.0g of mixed acid (49.0g99% nitric acid 0.77mol, 50.5g98% sulfuric acid ), remove the hot water at the same time, switch to ice water for cooling, and keep the temperature at 45~50°C. 3 The temperature of the solution was raised to 60~70°C, kept for one hour, and the phases were separated to obtain 127.5 g of the organic phase, a light yellow liquid with a freezing point of 26~28°C. The content of 2,4-dichloronitrobenzene was 98.9% and the molar yield was 98% by gas spectrometry. %.

Embodiment 2

[0027] Add m-dichlorobenzene 223.7g (98.5%, 1.50mol), dichloromethane 450g, anhydrous aluminum chloride 20.2g (0.15mol), Y5 molecular sieve 30g into a 2000ml magnetic stirring kettle, close the reaction kettle, start stirring, pass Add nitrogen dioxide 104g (99.5%, 2.25mol), oxygen 32g (about 1.0mol), slowly raise the temperature, control the pressure 1.0~5.0MPa, the final temperature does not exceed 100°C, react for 12 hours, cool down to about 30°C, and release the pressure , the remaining gas is absorbed with sodium hydroxide solution, after the pressure is released to normal pressure, press filtration, the filtrate is washed with 50ml of saturated NaHCO3 solution, the solvent is recovered at normal pressure, and then rectified under reduced pressure to obtain 2,4-dichloronitrobenzene 225.6g, content 99.1%, freezing point 28~29℃, molar yield 77.68%

Embodiment 3

[0029] Add m-dichlorobenzene 223.7g (98.5%, 1.50mol), dichloroethane 450g, anhydrous zinc chloride 27.2g (0.2mol), Y5 molecular sieve 30g into a 2000ml magnetic stirring kettle, seal the reaction kettle, start stirring, Introduce 138.7g (99.5%, 3.0mol) of nitrogen dioxide, 32g (about 1.5mol) of oxygen, slowly raise the temperature, control the pressure at 1.0~5.0MPa, the final temperature does not exceed 100°C, react for 12 hours, and cool down to about 30°C. Release the pressure, absorb the remaining gas with sodium hydroxide solution, release the pressure to normal pressure, press filter, wash the filtrate with 50ml of saturated NaHCO3 solution, recover the solvent under normal pressure, and then rectify under reduced pressure to obtain 2,4-dichloronitrate Benzene 236.50g, content 99.2%, molar yield 81.52%

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Abstract

The invention discloses a preparation method for 5-chloro-2-nitroaniline. The preparation method comprises the following steps: performing nitration by using m-dichlorobenzene as a starting material to prepare 2,4-dichloronitrobenzene, adding the 2,4-dichlorobenzene and a solvent into an autoclave, adding ammonia, performing high-pressure amination, after the amination is completed, performing cooling, performing pressure filtration, removing the solvent from a filtrate, and performing refining to obtain the target product 5-chloro-2-nitroaniline. The method provided by the invention has the following advantages: (1) nitrogen dioxide is used as a nitrating reagent to replace a traditional nitric acid-sulfuric acid mixed acid nitrating agent, so that no waste acid is produced, cleanliness of an industrial synthesis reaction is improved, and environmental pollution is reduced; and (2) after the amination is completed, by-product ammonium chloride is directly removed by pressure filtration, so that an amount of waste water is small, and an amination yield is high.

Description

technical field [0001] The invention relates to a preparation method of 5-chloro-2-nitroaniline. Background technique [0002] 5-Chloro-2-nitroaniline is a chemical intermediate that can synthesize a variety of pesticides, medicines and dyes. Chinese patent CN105175726B uses it to prepare high-refractive polyarylene sulfide sulfone films, which can be used to prepare new image sensors Use microlens film material. [0003] In the traditional production of 5-chloro-2-nitroaniline, m-dichlorobenzene is used as raw material to obtain 2,4-dichloronitrobenzene through nitration, and then through high-pressure amination to obtain 5-chloro-2-nitroaniline and ammonium chloride mixture, washed with methanol, recrystallized, refined, and dried to obtain 5-chloro-2-nitroaniline; [0004] Chinese patent CN1182104C proposes a kind of with 3-chloroaniline as starting raw material, formylate with formic acid in solvent, get 3-chloroformanilide after removing solvent, then 3-chloroformanil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/02C07C211/52C07C201/08C07C205/12
CPCC07C209/02C07C201/08C07C211/52C07C205/12
Inventor 张建华曹娇顾佳林李红梅
Owner 江苏优普生物化学科技股份有限公司
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