A kind of 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 The effect of industrial production and simple reaction process

Inactive Publication Date: 2012-02-15
LIAONING UNIVERSITY
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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 begun to be phased out.

Method used

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  • A kind of method for synthesizing 2,4-dichloroaniline

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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)

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

[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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Abstract

The invention relates to a method for synthesizing 2,4-dichloroaniline. The technical scheme adopted is as follows: in the presence of carbon monoxide and water, use 2,4-dinitrobenzene as a raw material, selenium as a catalyst, and alkali as a cocatalyst, or without any cocatalyst, carry out nitration in an organic solvent under high pressure Base selective reduction reaction, the molar ratio of 2,4-dichloronitrobenzene to water is 1:1~100; the molar amount of selenium is 0.2~10% of 2,4-dinitrobenzene; the molar amount of alkali is 2, 0-200% of 4-dinitrobenzene; the reaction temperature is 80-200°C, the reaction pressure is 1-6Mpa, and the reaction time is 2-10 hours. After the reaction is completed, cool to room temperature, release the reaction waste gas, and introduce oxygen Or air stirred for 1-2 hours, filtered and distilled. The invention uses selenium as a catalyst, the reduction selectivity is as high as over 99%, and the reaction is almost quantitative.

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 begun to be phased out. Contents of the invention [0003] In order to solve the above problems, the object of the present invention is to provide a method f...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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