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Method for high-selectivity preparation of 3,4-dichloroaniline

A dichloroaniline and high-selectivity technology, which is applied in the field of high-selectivity catalytic hydrogenation preparation 3, can solve the problems of low catalyst application times and high cost, and achieve the effects of low cost, reduced corrosion and high selectivity

Active Publication Date: 2014-04-02
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Disadvantages of this method: the catalyst is applied less frequently and the cost is too high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Add 64 g of 3,4-dichloronitrobenzene and 0.16 g of 3% Pt (water content 59.98%) catalyst containing additives into a stainless steel autoclave, close the autoclave, replace the air in the autoclave with nitrogen three times, and then Replace the nitrogen in the kettle with hydrogen three times and maintain a certain pressure in the kettle. Heat up to 85°C under stirring, maintain the reaction pressure at 1.75MPa, close the hydrogen valve after the reaction is over, let the gas out, open the autoclave to discharge, keep warm at about 75°C to filter out the catalyst, and use gas chromatography to analyze the reduction product, 3,4-dichloronitro The conversion rate of benzene is 100%, the selectivity of 3,4-dichloroaniline is 99.6%, and the dechlorination rate is 0.19%.

Embodiment 2

[0027] The catalyst was changed, and the influence of the Pt catalyst without promoters on the hydrogenation of 3,4-dichloronitrobenzene was investigated.

[0028] Add 64 g of 3,4-dichloronitrobenzene and 0.16 g of 3% Pt (water content 59.78%) catalyst into a stainless steel autoclave, seal the autoclave, replace the air in the autoclave with nitrogen three times, and then replace the autoclave with hydrogen Inner nitrogen three times and maintain a certain pressure in the kettle. Heat up to 85°C under stirring, maintain the reaction pressure at 1.75MPa, close the hydrogen valve after the reaction is over, let the gas out, open the autoclave to discharge, keep warm at about 75°C to filter out the catalyst, and use gas chromatography to analyze the reduction product, 3,4-dichloronitro The conversion rate of benzene is 100%, the selectivity of 3,4-dichloroaniline is 99.0%, and the dechlorination rate is 0.27%.

Embodiment 3

[0030] Increase the amount of catalyst to investigate the effect of catalyst amount on the hydrogenation of 3,4-dichloronitrobenzene.

[0031] 64 g of 3,4-dichloronitrobenzene and 0.18 g of 3% Pt (water content 59.98%) catalyst containing additives were added to a stainless steel autoclave, the autoclave was sealed, and the air in the autoclave was replaced with nitrogen for three times, and then Replace the nitrogen in the kettle with hydrogen three times and maintain a certain pressure in the kettle. Heat up to 85°C under stirring, maintain the reaction pressure at 1.75MPa, close the hydrogen valve after the reaction is over, let the gas out, open the autoclave to discharge, keep warm at about 75°C to filter out the catalyst, and use gas chromatography to analyze the reduction product, 3,4-dichloronitro The conversion rate of benzene is 100%, the selectivity of 3,4-dichloroaniline is 99.5%, and the dechlorination rate is 0.20%.

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PUM

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Abstract

The invention belongs to the technical field of fine chemical engineering, and relates to a method for preparing 3,4-dichloroaniline from 3,4-dichloronitrobenzene through high-selectivity catalytic hydrogenation. With 3,4-dichloronitrobenzene as raw material and in the presence of a Pt catalyst, 3,4-dichloroaniline is prepared through a catalytic hydrogenation reaction under the pressure of 1.0 MPa-3.0 MPa and at the temperature of 75-120 DEG C. With adoption of the method, the conversion rate of 3,4-dichloronitrobenzene is 100%, the selectivity of 3,4-dichloroaniline is greater than 99.6%, and the dechlorination rate is less than 0.20%. The Pt catalyst is safe to use, and has stable catalytic activity and high selectivity; a dechlorination inhibitor is not required to be added; through introduction of Fe2O3 into the Pt catalyst, a dechlorination phenomenon can be effectively inhibited, and the corrosion of dechlorination to a reaction container during reduction is reduced; and the method is not added with a solvent, overcomes the defect of the addition of the solvent, avoids the problems of pollution of the solvent to the environment and solvent recovery, reduces equipment investment, and reduces production costs.

Description

technical field [0001] The invention belongs to the technical field of fine chemicals, and relates to a method for preparing 3,4-dichloroaniline by using 3,4-dichloronitrobenzene as a raw material through highly selective catalytic hydrogenation. Background technique [0002] 3,4-Dichloroaniline is an important pesticide and dye intermediate, which is widely used in the synthesis of herbicides and azo dyes, and some of them are used as bioactive components in the synthesis of medicines. There are usually three production methods: iron powder reduction method, alkali sulfide reduction method and catalytic hydrogenation reduction method. Due to the problems of high cost and serious pollution in the iron powder reduction method and alkali sulfide reduction method, they have been eliminated. The current production process of 3,4-dichloroaniline mainly uses skeleton nickel as a catalyst and alcohol as a solvent to catalytically hydrogenate 3,4- Dichloronitrobenzene produces 3,4-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/36
Inventor 吴其建杜建国周亚苓
Owner CHINA PETROLEUM & CHEM CORP
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