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

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...

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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

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