Catalyst for synthesizing 3, 5-dichloroaniline, and preparation method and application of catalyst

Abstract

The invention discloses a catalyst for synthesizing 3, 5-dichloroaniline. The catalyst comprises a barium sulfate carrier, Pd, and an auxiliary agent metal, and the auxiliary agent metal is Mn, Fe, Co, Cu or Zn. In addition, the invention also provides a preparation method of the catalyst and a method for catalyzing hydrogenation of 3, 5-dichloronitrobenzene to synthesize 3, 5-dichloroaniline by using the catalyst. The catalyst is low in raw material cost, high in catalytic activity and good in selectivity,; when the catalyst is used for catalytic synthesis of 3, 5-dichloroaniline, no dechlorinating agent is needed, the raw material conversion rate reaches 100%, and the dechlorinating rate is 0.04% or lower. According to the catalyst prepared by adopting the method disclosed by the invention, active metal particles and a carrier are combined more firmly, are more highly dispersed and more uniform, the catalyst has good selectivity in reaction of catalyzing hydrogenation of 3, 5-dichloronitrobenzene to synthesize 3, 5-dichloroaniline, and the dechlorination rate is greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of noble metal catalysts, and in particular relates to a catalyst for synthesizing 3,5-dichloroaniline, 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 output of cyclic phthalimide agricultural fungicides has made 3,5-dichloroaniline become a trend that the supply exceeds the demand. At present, the synthetic methods of 3,5-dichloroaniline mainly include: [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 realize industrial production. [0004] (2) Chemical reduction method The chemical re...

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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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