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Catalytic hydrogenation method for preparing 3,4-dichloroaniline

A technology for dichloroaniline and catalytic hydrogenation, which is applied in 3 fields, can solve the problems of high price, difficult recovery of precious metals Ru and Pt, complicated preparation process, etc., achieves high reactivity and selectivity, and has obvious effects of inhibiting dechlorination.

Inactive Publication Date: 2007-05-16
ZHONGBEI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] U.S. Patent US 4760187 has reported the method for preparing 3,4-dichloroaniline by catalytic hydrogenation of 3,4-dichloronitrobenzene using Ru-Pt-Ni-Cr / C as a catalyst, the method of 3,4-dichloroaniline The selectivity is 98%, but the patented technology uses a quaternary active component as a catalyst, the catalyst preparation process is complicated, and the recovery of precious metals Ru and Pt is very difficult
Chinese patent CN 200510050594 uses Ru-Fe / Al 2 o 3 As a catalyst, directly obtain hydrogen from the catalytic cracking of alcohol solution for the catalytic hydrogenation of 3,4-dichloronitrobenzene to prepare 3,4-dichloroaniline, which can effectively inhibit the dechlorination and the selectivity of 3,4-dichloroaniline It is more than 90%, but the catalyst used in this patent technology also has the problem of complicated preparation process, and due to the use of Al 2 o 3 As a carrier, it also leads to an increase in the recovery cost of precious metal Ru
Chinese patent CN 02148509 uses Pd / NCT and Pt / NCT as catalysts respectively to prepare 3,4-dichloroaniline by hydrogenation, and the selectivity of 3,4-dichloroaniline reaches 99.2% and 99%. However, using carbon nano As a carrier, tubes are very expensive and difficult to implement in industry

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Add 5 g of 3,4-dichloronitrobenzene and 25 mL of methanol into a 75 mL autoclave, add 0.5 g of W-4 ​​type Raney-Ni catalyst, and 0.1 g of dechlorination inhibitor ethanolamine at the same time, close the autoclave, and open the H 2 Valve to feed H into the autoclave 2 , adjust the kettle pressure to 0.9MPa, stir and heat up to 80°C, react for 50min, close the H 2 Valve, open the autoclave after cooling, discharge, add in the distillation bottle after filtering, add 50mL water and a small amount of gac, in N 2 The solvent methanol was recovered by atmospheric distillation under protection, and the remaining liquid was hot-filtered to remove activated carbon, then cooled to precipitate crystals, and vacuum-dried to obtain 3.50 g of 3,4-dichloroaniline, which was 99.93% by mass according to gas chromatography analysis.

Embodiment 2

[0022] Add 5 g of 3,4-dichloronitrobenzene and 30 mL of methanol into a 75 mL autoclave, add 0.6 g of W-4 ​​type Raney-Ni catalyst, and 0.1 g of dechlorination inhibitor ethanolamine at the same time, close the autoclave, and open the H 2 Valve to feed H into the autoclave 2 , adjust the kettle pressure to 1.0MPa, stir and heat up to 90°C, react for 60min, close the H 2 Valve, open the autoclave after cooling, discharge, add in the distillation bottle after filtering, add 50mL water and a small amount of gac, in N 2 The solvent methanol was recovered by atmospheric pressure distillation under protection, and the remaining liquid was hot filtered to remove activated carbon, then cooled to precipitate crystals, and dried in vacuum to obtain 3.47 g of 3,4-dichloroaniline, which was 99.36% by mass according to gas chromatography analysis.

Embodiment 3

[0024] Add 5 g of 3,4-dichloronitrobenzene and 30 mL of methanol into a 75 mL autoclave, add 0.8 g of W-4 ​​type Raney-Ni catalyst, and 0.2 g of dechlorination inhibitor ethanolamine at the same time, close the autoclave, and open the H 2 Valve to feed H into the autoclave 2 , adjust the kettle pressure to 1.3MPa, stir and heat up to 80°C, react for 70min, close the H 2 Valve, open the autoclave after cooling, discharge, add in the distillation bottle after filtering, add 50mL water and a small amount of gac, in N 2 The solvent methanol was recovered by atmospheric pressure distillation under protection, and the remaining liquid was hot-filtered to remove activated carbon, cooled to precipitate crystals, and vacuum-dried to obtain 3.51 g of 3,4-dichloroaniline, which was 99.36% by mass according to gas chromatography analysis.

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PUM

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Abstract

The invention discloses a preparing method of 3, 4-dichloroaniline, which is characterized by the following: adopting 3, 4-dichloronitrobenzene as raw material and alcohol solution as solvent system; aerating H2 under 0.5-1.5Mpa at 80-120 Deg C in the condition of Raney-Ni catalyst and dechlorination inhibitor; proceeding catalytic hydrogenating reducing reaction to produce the product. The selectivity of 3, 4-dichloroaniline is more than 99%, whose dechlorination quantity is less than 2%.

Description

technical field [0001] The present invention relates to a preparation method of 3,4-dichloroaniline, in particular to a method for preparing 3,4-dichloroaniline by catalytic hydrogenation reduction method using 3,4-dichloronitrobenzene as raw material . Background technique [0002] 3,4-Dichloroaniline is an important chemical intermediate for medicines, pesticides, dyes, spices, etc., and has a wide range of uses. The synthesis methods of 3,4-dichloroaniline usually include iron powder reduction method, alkali sulfide reduction method and catalytic hydrogenation reduction method, and 3,4-dichloroaniline is prepared by reduction of 3,4-dichloronitrobenzene. [0003] The chemical reduction methods such as the iron powder reduction method under acidic conditions or the alkali sulfide reduction method under alkaline conditions are used to prepare 3,4-dichloroaniline although the cost is low, but a large amount of amine-containing toxic metal residues or hydrochloric acid-conta...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/36
Inventor 胡拖平陈宏博张学俊
Owner ZHONGBEI UNIV
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