Method for synthesising halogenated aromatic amine through hydrogenation in solvent-free condition

A halogenated arylamine, solvent-free technology, applied in the field of hydrogenation to synthesize halogenated arylamines, can solve the problems of few research reports, decreased catalytic activity, etc., and achieve the effects of reducing separation and purification, simple method, and improving reaction speed.

Active Publication Date: 2014-11-26
HUAWEI TEHCHNOLOGIES CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Supported metal catalysts are easy to sinter at high temperatures, which is a commonly observed phenomenon, but it is generally believed that the catalytic activity of supported metal catalysts decreases after sintering at high temperatures, so researchers pay more attention to how to avoid metal catalysts being sintered at high temperatures. Sintering occurs
However, there are very few research reports on utilizing the characteristics of sintering of supported metal catalysts at high temperature and exerting its beneficial effects.

Method used

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  • Method for synthesising halogenated aromatic amine through hydrogenation in solvent-free condition
  • Method for synthesising halogenated aromatic amine through hydrogenation in solvent-free condition
  • Method for synthesising halogenated aromatic amine through hydrogenation in solvent-free condition

Examples

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Embodiment 1 8

[0032] Examples 1 to 8 investigated the performance of the carbon-supported large particle size noble metal catalysts in the solvent-free liquid phase hydrogenation synthesis of halogenated arylamines after treatment at different calcination temperatures. The particle size is 800 mesh and the specific surface area is 1200m 2 / g of activated carbon, it was formulated into a slurry at a temperature of 80°C, and the H 2 PdCl 4solution, fully stirred evenly; after soaking for 2 hours, add NaOH solution to adjust the pH value to 7.5, and lower the temperature to room temperature, filter, and wash the filter cake with deionized water until neutral; then configure the filter cake into a slurry at 70°C , drop an excess of hydrazine hydrate solution, stir, filter, wash the filter cake with deionized water until neutral, and dry it in vacuum at 100°C to obtain a carbon-supported palladium catalyst; , 600, 700, 800, 900, and 1000°C for 5 hours to obtain different carbon-supported large...

Embodiment 17 20

[0044] Examples 17 to 26 investigated the performance of different carbon-supported large particle size noble metal catalysts in the solvent-free liquid-phase hydrogenation synthesis of halogenated arylamines. The particle size is 1000 mesh and the specific surface area is 1000m 2 / g of activated carbon used to prepare the catalyst, which was prepared into a slurry at a temperature of 90°C, and slowly added H 2 PdCl 4 or H 2 PtCl 6 solution, fully stirred evenly; after soaking for 5 hours, add ammonia water to adjust the pH value to 8.5, and lower the temperature to room temperature, filter, and wash the filter cake with deionized water until neutral; then configure the filter cake into a slurry at 60°C, Add excess formic acid solution dropwise, stir, filter, wash the filter cake with deionized water until neutral, and dry it in vacuum at 110°C to obtain a carbon-supported noble metal catalyst; particle size noble metal catalysts.

[0045] Add 200g of 3-chloro-4-methylnit...

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Abstract

The invention provides a method for synthesising halogenated aromatic amine through hydrogenation in a solvent-free condition. The method comprises the following step of: carrying out a liquid-phase hydrogenation reaction on the halogenated aromatic nitro compound shown in formula (I) under the action of hydrogen, in the absence of a solvent and a dehalogenation inhibitor under the action of a carbon-supported large-particle-size precious metal catalyst to prepare the halogenated aromatic amine shown in formula (II). The method provided by the invention is capable of achieving the effect of inhibiting a hydrogenation dehalogenation side reaction in the case of not adding a dehalogenation inhibitor, is high in target product selectivity, and is capable of remarkably increasing the reaction speed.

Description

(1) Technical field [0001] The invention relates to a method for synthesizing halogenated arylamine by hydrogenation under solvent-free conditions. (2) Background technology [0002] Halogenated aromatic amines are important raw materials for medical (agricultural) medicines, new materials, dyes and surfactants. Halogenated aromatic amines are generally prepared from corresponding halogenated aromatic nitro compounds through reduction reactions, including chemical reduction methods (iron powder reduction method, alkali sulfide reduction method, etc.), electrolytic reduction methods, and catalytic hydrogenation reduction methods. The chemical reduction method has disadvantages such as large environmental pollution, low product yield, and poor product quality, and has been gradually eliminated. Due to the large power consumption, high cost, low product yield, and the constraints of electrode materials and electrolysis equipment, the electrolytic reduction method is difficult ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/36B01J23/42B01J23/44
Inventor 张群峰马磊卢春山吕井辉李小年
Owner HUAWEI TEHCHNOLOGIES CO LTD
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