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Method for synthesizing 2, 4-dichloroaniline

A technology of dichloroaniline and dichloronitrobenzene, which is applied in chemical instruments and methods, preparation of organic compounds, preparation of amino compounds, etc., can solve problems such as serious environmental pollution, achieve high reduction selectivity, and facilitate large-scale Industrialized production, the effect of reducing the separation process

Inactive Publication Date: 2009-06-03
LIAONING UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this process is simple and has a high reduction conversion rate, it pollutes the environment seriously. It is a process that is banned by the state and has gradually been eliminated.

Method used

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  • Method for synthesizing 2, 4-dichloroaniline
  • Method for synthesizing 2, 4-dichloroaniline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] 19.2 g (0.1 mol) of 2,4-dichloronitrobenzene, 0.32 g (4 mmol) of Se, 20 mL (1.1 mol) of water, 4 g (50 mmol) of sodium acetate and 0.2 L of toluene were added to a 1000 mL autoclave. After closing the autoclave and checking the airtightness, nitrogen gas was introduced to a pressure of 2 MPa, and then released. Replace like this 3 times, to remove the air in the autoclave, feed carbon monoxide to a pressure of 2Mpa, then deflate, and then feed carbon monoxide to a pressure of 3Mpa. Heat to 140°C to react for 4 hours, cool to room temperature, release the waste gas after reaction to normal pressure, stir in the air for 2 hours, filter out the catalyst, and distill the filtrate under reduced pressure to obtain the product 2,4-dichloroaniline 16.1 g (0.1 mol), yield 99%.

Embodiment 2

[0023] Reaction temperature, water yield, reaction time are as follows, and experimental method and other conditions are with embodiment 1, and yield is as follows:

[0024] Water volume (mol) 2,4-Dichloronitrobenzene to water molar ratio Reaction temperature (°C) Response time (hr) Yield (%)

[0025] It can be seen from the table that as the amount of water increases, the yield decreases, and the molar ratio of 2,4-dichloronitrobenzene to water is 1:1-40.

Embodiment 3

[0027] The consumption of Se is as follows, and experimental method and other conditions are with embodiment 1, and yield is as follows:

[0028] Se amount (mmol) 0.2 0.5 1 2 3 5 9 10 Yield (%) 45 85 99 99 94 93 92 92

[0029] It can be seen from the table that with the increase of the amount of Se, the yield does not increase much. In consideration of cost reduction, the amount of Se is preferably 1% to 10% of that of 2,4-dichloronitrobenzene.

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PUM

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Abstract

The invention relates to a method for synthesizing 2, 4-dichloroaniline. The adopted technical scheme is as follows: in the presence of carbon monoxide and water, 2, 4-dinitrobenzene serves as the raw material, selenium serves as a catalyst, and alkali serves as a cocatalyst, or no cocatalyst is added; a nitro selective reduction reaction is conducted in organic solvent under high pressure; the molar ratio of 2, 4-dichloronitrobenzene and water is 1:1 to 100; the mole amount of selenium is 0.2 to 10 percent of 2, 4-dinitrobenzene; the mole amount of alkali is 0 to 200 percent of 2, 4-dinitrobenzene; the reaction temperature is 80 to 200 DEG C; the reaction pressure is 1 to 6Mpa, the reaction time is 2 to 10 hours; and after reaction, the organic solvent is cooled to room temperature; reaction waste gas is exhausted; oxygen or air is introduced into the organic solvent and agitated for 1 to 2 hours; and the organic solvent is filtered and distilled. The method uses selenium as the catalyst, and the reduction selectivity is up to more than 99 percent, which is close to the reduction selectivity of a quantitative reaction.

Description

technical field [0001] The invention relates to the field of chemical synthesis methods, in particular to a method for synthesizing 2,4-dichloroaniline by using carbon monoxide and water to catalyze the reduction of 2,4-dichloronitrobenzene under high pressure. Background technique [0002] 2,4-Dichloroaniline, as an important organic synthesis intermediate and raw material, is widely used in the fields of medicine, pesticide, dyestuff and so on. At present, the selective reduction of 2,4-dichloronitrobenzene is the main method for preparing 2,4-dichloroaniline. The reduction method currently used in industrial production is iron powder reduction method. Although this process is simple and has a high reduction conversion rate, it pollutes the environment seriously. It is a process that is banned by the state and has gradually been eliminated. Contents of the invention [0003] In order to solve the above problems, the object of the present invention is to provide a metho...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/36
Inventor 刘晓智于强张荷新李春荣王冠中许浩然陈霞
Owner LIAONING UNIVERSITY
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