Catalytic hydrogenation method for preparing halogenated aromatic amine from halogenated arene nitro compounds

A technology of nitro compounds and halogenated aromatics, which is applied in the field of catalytic hydrogenation of nitro compounds of halogenated aromatics to prepare halogenated aromatic amines, which can solve problems such as environmental pollution and increase the burden of product separation procedures, and reduce costs and production accidents risks, effects of decontamination

Active Publication Date: 2008-09-17
CHANGZHOU INST OF ENERGY STORAGE MATERIALS &DEVICES
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, the main problems encountered in the catalytic hydrogenation method are: (1) the catalytic hydrogenation process of halogenated aromatic hydrocarbon nitro compounds is often accompanied by dechlorination reaction, and the inhibition of dechlorination reaction is to prevent equipment corrosion and improve the yield of halogenated aromatic amines. , one of the key factors affecting process economy
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Method used

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  • Catalytic hydrogenation method for preparing halogenated aromatic amine from halogenated arene nitro compounds
  • Catalytic hydrogenation method for preparing halogenated aromatic amine from halogenated arene nitro compounds

Examples

Experimental program
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Effect test

Embodiment 1

[0020] Embodiment 1 ortho-chloronitrobenzene (o-CNB) hydrogenation

[0021] Add 1.5g o-CNB, 150mg reduced Ni / TiO to a 50ml stainless steel reactor 2 -I catalyst, Ni / TiO 2 -I catalyst impregnated TiO with nickel nitrate solution 2 The powder is prepared, and the mass content of Ni in the catalyst is 15%. Tighten the reactor, purging with high-purity nitrogen for 3 minutes at room temperature, and then using 2MPa H 2 Replace 2 times to get rid of the air in the reactor. The reaction kettle was preheated in a constant temperature water bath at 35°C for 20min, and then 4MPa H 2 , 10.5MPa CO 2 , start stirring, react at 35°C for 50 min, and analyze the product by gas chromatography after being diluted with ethanol. The conversion of o-CNB was 82%, and the selectivity of o-chloroaniline was 99.8%.

Embodiment 2

[0026] Embodiment 2 m-chloronitrobenzene (m-CNB) hydrogenation

[0027] Add 1.5g m-CNB and 150mg catalyst in a 50ml reactor, the catalyst is the same as in Example 1. Tighten the reaction kettle, purging with high-purity nitrogen, H at room temperature 2 After the replacement, the reactor was preheated in a constant temperature water bath at 35°C for 20 minutes, and then 4MPa H 2 , 11MPa CO 2 , start stirring, react at 35°C for 80 min, and analyze the product by gas chromatography after being diluted with ether. The conversion rate of m-CNB was 100%, and the selectivity of m-chloroaniline was 99.5%.

Embodiment 3

[0028] Embodiment 3 p-chloronitrobenzene (p-CNB) hydrogenation

[0029] Add 1.5g p-CNB, 150mg catalyst in 50ml reactor, catalyst is the same as embodiment 1. Tighten the reaction kettle, purging with high-purity nitrogen, H at room temperature 2 After the replacement, the reactor was preheated in a constant temperature water bath at 35°C for 20 minutes, and then 4MPaH 2 , 11MPa CO 2 , start stirring, react at 35°C for 30min, and analyze the product by gas chromatography. The conversion rate of p-CNB was 50.5%, and the selectivity to p-chloroaniline was 99.2%.

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Abstract

The invention relates to a method of preparing halogen aromatic amine by catalyzing aryl halide nitrocompound through selective hydrogenation. The method comprises the following steps: in scCO2, a non-noble metal Ni catalyst is adopted to catalyze the aryl halide nitrocompound and prepare the halogen aromatic amine through selective hydrogenation under the low temperature ranging from 31 to 100 DEG C; in the scCO2, the hydrogenation speed of -NO2 group in the aryl halide nitrocompound is higher than the speed in ethanol obviously, and the dehalogenation reaction is markedly inhibited, so that the selectivity of the halogen aromatic amine is more than 99 percent is realized. The cost of the Ni catalyst is lower than a noble metal catalyst; the Ni catalyst has ferromagnetism at the same time, thereby providing the possibility to the reactor operation and the catalyst separating by adopting an external magnetic field.

Description

technical field [0001] The invention relates to a method for preparing halogenated aromatic amines through catalytic hydrogenation of halogenated aromatic hydrocarbon nitro compounds. It specifically involves the use of ferromagnetic non-noble metal Ni as a catalyst to catalyze halogenated aromatic hydrocarbon nitro compounds in supercritical carbon dioxide (scCO 2 ) medium to prepare halogenated aromatic amines by hydrogenation. Background technique [0002] Halogenated aromatic amines are intermediates in the production of important chemical products such as pesticides, medicines, dyes, pigments and petroleum solvents. [0003] Catalytic hydrogenation of halogenated aromatic nitro compounds is an effective method for preparing halogenated aromatic amines. At present, the main problems encountered in the catalytic hydrogenation method are: (1) the catalytic hydrogenation process of halogenated aromatic hydrocarbon nitro compounds is often accompanied by dechlorination rea...

Claims

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Application Information

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IPC IPC(8): C07C209/36C07C211/52
Inventor 赵凤玉孟祥春才淑霞
Owner CHANGZHOU INST OF ENERGY STORAGE MATERIALS &DEVICES
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