Method for preparing 4-amino diphenylamine by catalytic hydrogenation

A technology of aminodiphenylamine and catalytic hydrogenation, which is applied in the field of preparation of 4-aminodiphenylamine, can solve problems such as difficulty in satisfying stable operation and production, inevitable loss of catalyst, and small proportion of catalyst cost, etc., to solve the problem of recycling, The effect of less catalyst loss and low cost of use

Active Publication Date: 2010-04-07
JIANGSU YANGNONG CHEM GROUP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the sedimentation method and the filtration method are only suitable for batch reactions, and at the same time, the catalyst inevitably loses small particles, which can be used for the production of pharmaceutical intermediates and other products with high added value, a small proportion of the cost of the catalyst, and small scale; However, when sintered tubes are used to filter precious metal catalysts, the filtration resistance is large, the recoil effect is poor, regular cleaning is required, and the service life of sintered tubes is short, which makes it difficult to meet the needs of large-tonnage, continuous, long-period, stable production of 4-aminodiphenylamine.
According to another CN1167665C report, a combination of a settler and a magnetic separator is used to separate the hydrogenation catalyst. The magnetic separator needs to be cleaned regularly, and the loss of part of the catalyst is still unavoidable.

Method used

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  • Method for preparing 4-amino diphenylamine by catalytic hydrogenation
  • Method for preparing 4-amino diphenylamine by catalytic hydrogenation
  • Method for preparing 4-amino diphenylamine by catalytic hydrogenation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1A

[0042] The alkali catalyst adopts fresh tetramethylammonium hydroxide to prepare the condensation liquid mixture after the reaction of nitrobenzene and aniline.

[0043] Concentrate 285 g of 25% tetramethylammonium hydroxide aqueous solution to 35% at 55° C. and 3000 Pa. Then add 347g of aniline, and distill off the azeotropic product at 65°C and 5500Pa to make the molar ratio of water and alkali = 5.5:1. Under this condition, add 96.6g of nitrobenzene dropwise to the reaction solution within 1h and react for another 4h During the process, the azeotrope is still continuously distilled, and the reaction conditions are controlled to be 75 ° C and 5500 Pa. After the reaction, the shrinkage mixture is 500 g.

[0044] The condensate was analyzed by high-performance liquid chromatography, and the mass fractions of each component were: aniline 64.20%, nitrobenzene 0.73%, 4-nitrosodiphenylamine 26.60%, 4-nitrodiphenylamine 4.64%, phenazine 0.19% , Azobenzene 3.63%.

Embodiment 1B

[0046] The alkali catalyst adopts recovered tetramethylammonium hydroxide, and adds 4% fresh tetramethylammonium hydroxide to prepare the condensation liquid mixture after the reaction of nitrobenzene and aniline.

[0047] 402g of the water layer recovered after a hydrogenation reaction (the mass fraction of tetramethylammonium hydroxide was measured as 17.05%, and the recovery rate was 96.2%) was concentrated to 35% at 55°C and 3000Pa, and then 7.8g was added Fresh 35% tetramethylammonium hydroxide solution. Other operating procedures are the same as in Example 1A.

[0048] The condensate was analyzed by high-performance liquid chromatography, and the mass fractions of each component were: aniline 64.21%, nitrobenzene 0.65%, 4-nitrosodiphenylamine 27.3%, 4-nitrodiphenylamine 4.15%, phenazine 0.21% , Azobenzene 3.48%. Tetramethylammonium hydroxide has no obvious effect on the condensation reaction after being recovered and used mechanically.

Embodiment 2A

[0050] Attached figure 1 In the two-stage catalytic hydrogenation process shown, the first-stage hydrogenation catalyst is a commercially available 5% palladium / carbon catalyst, and the second-stage hydrogenation catalyst is a self-made ordinary skeleton nickel catalyst made of aluminum-nickel alloy powder.

[0051] The condensation solution 500g of embodiment 1A is put into one-stage hydrogenation autoclave, add 150g water and 1.5g 5% palladium / carbon catalyst simultaneously, replace 4 times with nitrogen and hydrogen respectively, feed hydrogen then, control reactor pressure is 3.5MPa, the temperature is 70°C, and the reaction is over when no hydrogen is absorbed; after cooling down to room temperature, the reaction liquid is released through the filter valve, and the catalyst is left in the kettle to continue to apply; To neutrality, the washing water and the separated water layer are combined and extracted with 150g aniline, and the extracted water layer is applied mechani...

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Abstract

The invention provides a method for preparing 4-amino diphenylamine by catalytic hydrogenation. The method adopts two sections of hydrogenation reaction processes, and comprises the following steps: performing the condensation reaction of condensation solution formed by the condensation reaction of nitrobenzene and aniline which serve as raw materials under an alkaline condition by using using a noble metal hydrogenation catalyst and a nickel catalyst sequentially so as to make the conversion rate of 4-nitroso diphenylamine, 4-nitro diphenylamine and azoxybenzene achieve 100 percent; and separating the noble metal hydrogenation catalyst and the nickel catalyst by using a two-stage membrane separation component system to avoid the loss of small particles of catalyst. At the same time, the method has high degree of automation and can easily realize the continuous hydrogenation process.

Description

technical field [0001] The invention relates to a preparation method of 4-aminodiphenylamine, in particular to a method for preparing 4-aminodiphenylamine by catalytic hydrogenation after condensation under alkaline conditions with aniline and nitrobenzene as raw materials. Background technique [0002] 4-aminodiphenylamine (4-aminodiphenylamine), also known as p-aminodiphenylamine, N-phenyl-p-phenylenediamine, blue base RT, blue base RT or RT base, is an important fine chemical intermediate, Mainly used in the production of p-phenylenediamine rubber antioxidants 4010NA, 4020, etc. In addition, it can also be used to synthesize blue salt VRT, which is used in the fields of dyestuff, textile, printing and pharmaceutical industries. [0003] There are many production methods for 4-aminodiphenylamine, and the currently industrialized methods mainly include aniline method, formanilide method, diphenylamine method and nitrobenzene method. These several methods all first synthes...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/55C07C209/36C07C209/38C07C209/84B01D61/58
Inventor 程晓曦许金来袁源顾志强丁克鸿王秋萍万保坡顾克军
Owner JIANGSU YANGNONG CHEM GROUP
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