A kind of catalyst for synthesizing 3,5-dichloroaniline and its preparation method and application

Abstract

The invention discloses a catalyst for synthesizing 3,5-dichloroaniline, comprising a barium sulfate carrier, Pd and an auxiliary metal, wherein the auxiliary metal is Mn, Fe, Co, Cu or Zn. In addition, the present invention also provides a preparation method of the catalyst and a method for catalyzing the hydrogenation of 3,5-dichloronitrobenzene to synthesize 3,5-dichloroaniline by using the catalyst. The catalyst of the invention has low raw material cost, high catalytic activity and good selectivity, and when used for catalyzing synthesis of 3,5-dichloroaniline, no dechlorination agent is required, the conversion rate of the raw material reaches 100%, and the dechlorination rate is below 0.04% . The catalyst prepared by the method of the present invention has stronger binding between the active metal particles and the carrier, and is more highly dispersed and uniform, and has good performance in catalyzing the hydrogenation of 3,5-dichloronitrobenzene to synthesize 3,5-dichloroaniline. selectivity, greatly reducing the dechlorination rate.

Description

technical field [0001] The invention belongs to the technical field of precious metal catalysts, and in particular relates to a catalyst for synthesizing 3,5-dichloroaniline and a preparation method and application thereof. Background technique [0002] 3,5-Dichloroaniline is an important intermediate of pesticides, medicines, dyes and pigments, and is widely used in the synthesis of medicines, dyes and plant growth promoters. Among them, the increase in the production of cyclophthalimide agricultural fungicides has made 3,5-dichloroaniline become a trend in short supply. At present, the synthetic method of 3,5-dichloroaniline mainly includes: [0003] (1) Electrolytic reduction method Electrolytic reduction method has been in the research stage due to the constraints of electrode materials, equipment, cost and other factors, and this process route has not been able to achieve industrial production. [0004] (2) Chemical reduction method The chemical reduction method of ir...

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Problems solved by technology

[0003] (1) Electrolytic reduction method The electrolytic reduction method has been stuck in the research stage due to the constraints of electrode materials, equipment, cost and other factors, and the process route has not been able to achieve industrial production

[0004] (2) Chemical reduction method The chemical reduction method of iron powder will produce more wastewater, which is very difficult to deal with and causes serious environmental pollution. The alkali sulfide reduction method has a high cost and cannot obtain an ideal yield.

[0005] (3) The publication date of 1,3,5-trichlorobenzene ammonia solution method is May 31, 2017, and the Chinese patent document with application number 201611235021.7 discloses a method using 1,3,5-trichlorobenzene in transition metal A synthetic method for obtaining 3,5-dichloroaniline by ammonolysis under catalysis, which is simple in operation and short in reaction steps, but has the problem of low yield (<93%)

[0006] (4) Polychlorinated nitrobenzene hydrogenation route In order to avoid environmental pollution, people focus on the research of environmentally friendly catalytic hydrogenation reduction method, but this process also has the problem of dechlorination while hydrogenation

The date of publication is June 23, 2004, and the Chinese patent application document with application number 02148509.7 discloses that Pd, Pt / CNT (carbon nanotubes) are used as catalysts for catalytic hydrogenation, and the dehalogenation rate is reduced to 0.1%, but due to The cost of carbon nanotubes is too high to achieve industrial production

In addition, other literatures use chemical reagents such as ethanolamine and morpholine to add dechlorination inhibitors to the reaction system, which can also achieve low dechlorination rates. Difficulties

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