Method for using parachloronitrobenzene to prepare parachloroaniline through selective hydrogenation

Abstract

The invention provides a method for using parachloronitrobenzene to prepare parachloroaniline through selective hydrogenation. The method comprises the steps that a catalyst containing platinum and titanium dioxide to catalyze parachloronitrobenzene to prepare parachloroaniline through selective hydrogenation under a hydrogen environment and a heating condition, and a dechlorinating side reactionsin the hydrogenation process are sharply decreased, wherein the catalyst is Pt / TiO2 / SBA-15 catalyst. The catalyst is used for presenting superior catalytic activity in the process of catalyzing parachloronitrobenzene to prepare parachloroaniline through selective hydrogenation, the conversion rate and the selectivity are very high, both can reach 99% or more, and the dechlorinating side reactionsare sharply decreased. The composite nanostructure catalyst Pt / TiO2 / SBA-15 used in the method is simple to prepare, short in production cycle, and low in platinum loading capacity, accordingly the catalyst cost is low, high temperature treatment is not needed, and a reduction agent does not need to be added in the preparation process. The platinum dispersity is good, and the catalytic activity ishigh.

Description

technical field [0001] The invention belongs to the field of catalytic hydrogenation, in particular to a method for preparing p-chloroaniline by selective hydrogenation of p-chloronitrobenzene. Background technique [0002] p-Chloroaniline is an important organic intermediate widely used in the synthesis of dyes, medicines and pesticides. At present, most p-chloroanilines are produced by reducing p-chloronitrobenzene. The reduction methods mainly include metal reduction method, electrochemical reduction method, non-hydrogen reducing agent reduction method, catalytic hydrogenation reduction method, etc., among which catalytic hydrogenation The reduction method has advanced technology and high yield, which is more in line with the requirements of modern chemical industry for atom economy; among them, the catalytic hydrogenation method of precious metals occupies the main position. In the past, the heterogeneous catalytic reduction method under high temperature and pressure was...

AI Technical Summary

Problems solved by technology

However, there are always some problems in the above-mentioned prior art: as some preparation conditions are harsh in the preparation method, the reagents used are not friendly to the environment, the dispersibility of platinum is not good, and the particle size is relatively large

At present, the common methods of preparing platinum-based catalysts at home and abroad, such as impregnation method, sol-gel method, and ion exchange method, have disadvantages such as complicated preparation process, easy aggregation of platinum nanoparticles, and non-green, which affect the overall performance of the catalyst.

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