Method for preparing 3-chloro-4-methylaniline through catalytic hydrogenation

A technology for catalytic hydrogenation and methylaniline, which is applied in the preparation of amino compounds, chemical instruments and methods, preparation of organic compounds, etc., can solve the problems of reduction and high catalyst cost, and achieves simple process, high selectivity and good product quality. Effect

Active Publication Date: 2012-11-21
中国中化股份有限公司 +1
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Problems solved by technology

[0005] In order to overcome the occurrence of side reactions of dechlorination of 3-chloro-4-methylaniline by catalytic hydrogenation of 3-chloro-4-methylnitrobenzene in the prior art and the problems of high catalyst cost, the invention provides a A method for preparing 3-chloro-4-methylaniline by catalytic hydrogenation, using this method to prepare 3-chloro-4-methylaniline with a selectivity of more than 99.9% and a yield of more than 99%, which can suppress the occurrence of dechlorination side reactions, Moreover, the process is simple, the operating conditions are mild, the pollution is small, the catalyst activity is high, the activity is stable, it can be applied repeatedly, and the cost of the catalyst is reduced

Method used

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  • Method for preparing 3-chloro-4-methylaniline through catalytic hydrogenation

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Embodiment 1

[0023] In a 500ml stainless steel high-pressure reactor, add 40.0g 3-chloro-4-methylnitrobenzene, 0.12g Pd-Fe / C catalyst (Pd content 5%, Fe content 0.8%), 120ml 95% ethanol-water solution (mass content ), close the reactor, replace the air with nitrogen 3 times, 0.2MPa each time, and replace the nitrogen with hydrogen 3 times, 0.2MPa each time. Add hydrogen to 2.0MPa, then raise the temperature to 65°C, start stirring, the hydrogen in the reactor drops to 1.5MPa, then add hydrogen to 2.0MPa, wait until the reading of the hydrogen pressure gauge no longer drops, the reaction is complete, cool down to room temperature, and use Nitrogen replaces the hydrogen in the autoclave, opens the reactor, takes out the reaction solution, filters out the catalyzer, and the filtrate distills off the solvent, obtains the 32.7g3-chloro-4-methylaniline product, analyzes its content with gas chromatography, and the results show that 3 -Chloro-4-methylaniline selectivity 99.92%, 3-chloro-4-methyla...

Embodiment 2

[0025] Except using 120ml 90% ethanol-water solution as solvent, other steps are identical with embodiment 1, obtain 32.7g3-chloro-4-methylaniline product, the content of each group of gas chromatography analysis product, the result shows, 3-chloro-4 -Methylaniline selectivity 99.90%, 3-chloro-4-methylaniline yield 99.0%.

Embodiment 3

[0027] Except using 120ml dehydrated alcohol as solvent, other steps are identical with embodiment 1, obtain 32.7g3-chloro-4-methylaniline product, the content of each group of product of gas chromatography analysis, the result shows, 3-chloro-4-methylaniline The selectivity of aniline is 99.95%, and the yield of 3-chloro-4-methylaniline is 99.0%.

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Abstract

The invention belongs to the field of organic synthesis and relates to a method for preparing 3-chloro-4-methylaniline through catalytic hydrogenation. The method comprises the steps of using 3-chloro-4-methylnitrobenzene as raw material and alcohol or alcohol-water as solvent, and performing hydrogenation reduction at the presence of a two component Pd-Fe/C catalyst to obtain the final product. The obtained 3-chloro-4-methylaniline has a selectivity of over 99.9% and a yield of over 99%. The method for preparing 3-chloro-4-methylaniline provided by the invention has the advantages of simple process, mild operating condition, little pollution, and high activity and selectivity of the used catalyst, and can effectively reduce production costs compared with the traditional process. The catalyst used can be used repeatably.

Description

technical field [0001] The invention belongs to the field of organic synthesis and relates to a method for preparing an organic intermediate, in particular to a method for preparing 3-chloro-4-methylaniline by catalytic hydrogenation. Background technique [0002] 3-Chloro-4-methylaniline is an important intermediate in the synthesis of pigments and pesticides. Its synthesis mainly includes iron powder reduction method, alkali sulfide reduction method and catalytic hydrogenation method. Iron powder reduction process and alkali sulfide reduction process to prepare 3-chloro-4-methylaniline, the amount of three wastes is large, and the treatment cost is high. The catalytic hydrogenation reduction method, which has the advantages of atomic economy, environmental friendliness and high product quality, can effectively solve the shortcomings of high pollution in the iron powder reduction method and the alkali sulfide reduction method. [0003] The catalytic hydrogenation reductio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/36B01J23/89
Inventor 李付刚孙兵张阳
Owner 中国中化股份有限公司
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