Method and catalyst for synthesizing chloroaniline from chloronitrobenzene by virtue of selective catalytic hydrogenation

A technology for chlorinated nitrobenzene and chlorinated aniline, applied in the field of synthesizing chlorinated aniline, can solve the problems of reduced reaction yield, easy dechlorination, catalyst poisoning and the like, and achieves high catalytic activity, good stability and low cost. Effect

Active Publication Date: 2015-03-18
YANTAI INST OF COASTAL ZONE RES CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Generally, hydrogenation catalysts such as skeleton Ni and Pd / C are used, but they are easy to dechlorinate, which will lead to catalyst poisoning and reduce the yield of the reaction.
At this stage, there are no reports or patents on the use of supported bimetallic catalysts to catalyze the selective hydrogenation of chloronitrobenzene to prepare chloroanilines.

Method used

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  • Method and catalyst for synthesizing chloroaniline from chloronitrobenzene by virtue of selective catalytic hydrogenation
  • Method and catalyst for synthesizing chloroaniline from chloronitrobenzene by virtue of selective catalytic hydrogenation
  • Method and catalyst for synthesizing chloroaniline from chloronitrobenzene by virtue of selective catalytic hydrogenation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Embodiment 1 Preparation of selective hydrogenation supported bimetallic catalyst

[0024] Crush activated carbon, sieve activated carbon within the range of 200-300 mesh, add activated carbon and 17% HNO to a three-necked flask 3 solution (solid-to-liquid mass ratio: 1:10), stirred and refluxed at 80°C for 3 hours, washed with distilled water until neutral, filtered, and dried at 110°C to obtain an activated carbon carrier. Add 4g of carrier and 60ml of distilled water in a 250ml three-necked flask, and add 3.3ml of chloroplatinic acid solution (12.15g / L) and 0.81g of CoCl under stirring 2 .6H 2 O, heated to 80 °C, stirred for 2h; then added Na 2 CO 3 solution, adjust the pH to 10, stir for 30 min, and wash with deionized water several times until no Cl ions exist in the filtrate. Then drop to room temperature, add 2.1g NaBH under stirring condition 4 Carry out reduction for 2h, wash with deionized water several times until the filtrate is neutral, and dry at room...

Embodiment 2

[0028] Embodiment 2 The impact of different supported bimetallic catalysts on the selective hydrogenation of 4-chloronitrobenzene

[0029] Weigh 15 mg of the catalyst prepared in Example 1, add it to a 100 ml three-necked flask, add 80 ml of methanol solution of 4-chloronitrobenzene with a concentration of 50 mmol / L, and stir the reactant with a magnetic stirrer for 5 min; then Pass N 2 , do this three times, and then pass H 2 , H 2 The flow rate is controlled within the range of 10-15ml / min, the reaction temperature is controlled at 30°C, and the reaction pressure is normal pressure. Depending on the selective hydrogenation rate of 4-chloronitrobenzene catalyzed by different catalysts, the reaction time is also different. Same, the specific dechlorination results are shown in Table 2.

[0030] Table 2 Effects of different supported bimetallic catalysts on the selective hydrogenation of 4-chloronitrobenzene

[0031] Reaction substrate

Embodiment 32

[0032] The effect of embodiment 32.0%Pt-0.5%Rh / C on the selective hydrogenation of different chloronitrobenzenes

[0033] Take by weighing the 2.0%Pt-0.5%Rh / C catalyst that 15mg embodiment 1 prepares, join in the there-necked flask of 100ml, add concentration and be the methanol solution 80ml of the chlorinated nitrobenzene of 50mmol / L, stir under magnetic stirrer Allow the reactant to be adsorbed for 5min; then pass N 2 , do this three times, and then pass H 2 , H 2 The flow rate is controlled within the range of 10-15ml / min, the reaction temperature is controlled at 30°C, and the reaction pressure is normal pressure. Depending on the selective hydrogenation rate of different reaction substrates, the reaction time is also different. The specific dechlorination results See Table 3.

[0034] Table 32.0%Pt-0.5%Rh / C Effect on Selective Hydrogenation of Different Chloronitrobenzenes

[0035]

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Abstract

The invention relates to a method for synthesizing chloroaniline and particularly relates to a method and a catalyst for synthesizing chloroaniline from chloronitrobenzene by virtue of selective catalytic hydrogenation. According to the method, a supported noble metal catalyst is utilized, hydrogen serves as a hydrogen source, chloronitrobenzene is subjected to selective hydrogenation in a liquid phase system to generate chloroaniline, and the selective hydrogenation process is presented by the following formula in the specification by virtue of liquid chromatography-mass spectrometric detection. The method is high in efficiency and reaction selectivity, mild in reaction condition and low in cost, and the operation is easily controlled.

Description

technical field [0001] The invention relates to a method for synthesizing chloroaniline, in particular to a method for synthesizing chloroaniline through selective catalytic hydrogenation of chloronitrobenzene and a catalyst thereof. Background technique [0002] Chloroaniline is an important class of pesticide and pharmaceutical organic intermediates, widely used in the synthesis of pharmaceuticals, dyes, pigments and other fine chemical products. Among them, o-chloroaniline can be used in the color base of dyes, as the diazo component of azo dyes and as intermediates for the manufacture of medicines and pesticides; Nitrogen dyes etc. [0003] At present, the industry mainly adopts iron powder reduction, sodium sulfide or hydrazine hydrate reduction, electrochemical or photocatalytic reduction, sulfonated ammonolysis and liquid phase catalytic reduction to prepare chloroaniline from nitrochlorobenzene. Among them, although the cost of the iron powder reduction method is l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/36B01J23/89B01J23/46B01J23/52
Inventor 夏传海马宣宣刘苏静孙秀敏杨翠云王建华
Owner YANTAI INST OF COASTAL ZONE RES CHINESE ACAD OF SCI
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