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Preparation method for p-aminodiphenylamine

A technology for p-aminodiphenylamine and aniline, which is applied in the field of industrial preparation of p-aminodiphenylamine, and can solve problems such as catalyst activation, complex operating units in the separation process, increased risk of reduction and post-processing units, increased equipment investment and operating costs, etc. , to achieve the effect of accurate and flexible adding operation, reducing labor intensity, and simplifying the separation process

Inactive Publication Date: 2012-11-28
山西翔宇化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although these methods have achieved results in terms of conversion rate, product quality, industrialized production and environmental pollution, there are some shortcomings: the one is that the activation, separation and recovery of the catalyst are complex and the operation unit is complicated, and the addition cannot be quantitatively controlled. Second, the use of volatile, flammable and explosive short-chain alcohols as hydrogenation solvents in the reduction reaction process increases the risk in the reduction and post-processing unit operations, and increases the risk for the reduction process. The follow-up separation operation unit added for the separation of alcohol will increase equipment investment and operating costs, and increase production costs

Method used

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  • Preparation method for p-aminodiphenylamine
  • Preparation method for p-aminodiphenylamine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] condensation reaction

[0053] The condensation reaction is to keep the vacuum degree of the reaction system at -0.09MPa, adjust the feed amount of raw materials to be 9L / hr of aniline, 3L / hr of nitrobenzene, and 10L / hr of composite alkali catalyst, and enter the primary condensation reaction kettle. Use the circulating pump at the bottom of the tank to carry out heating and dehydration reaction in the condensation liquid evaporator. The condensation liquid evaporator uses isopropanol as the heat medium. After heating and vaporizing the isopropanol with low-pressure steam, the condensation liquid entering the evaporator is circulated and heated. The cooling water removed by vacuum contains a small amount of aniline and enters the aniline water storage tank. The reaction temperature is controlled at 80°C, and the circulation flow rate is controlled at 400L / hr. After the liquid level in the primary condensation tank reaches a certain level, it enters the secondary tank or...

Embodiment 2

[0071] A preparation method of p-aminodiphenylamine, carried out according to the following steps:

[0072] first step, condensation

[0073] Pass nitrobenzene, aniline and composite base catalyst into the reaction kettle for condensation reaction to generate condensation liquid;

[0074] The weight percentage concentration of described composite base catalyst is 25%; The volume ratio of described nitrobenzene, aniline and composite base catalyst is 1: 8: 8;

[0075] The condensation reaction conditions are as follows: the reaction temperature is 85°C, the reaction time is 3 hours, and the reaction pressure is -0.090~-0.098MPa;

[0076] The second step is to add alkali to form a salt

[0077] Add solid caustic soda to the condensed liquid, then stir and filter to obtain a qualified condensed liquid; the stirring time for salt formation is 1 hour, and the CO in the qualified condensed liquid 3 -2 The weight percentage content is 0.3%, and the salt-forming temperature is 60°...

Embodiment 3

[0094] A preparation method of p-aminodiphenylamine, carried out according to the following steps:

[0095] first step, condensation

[0096] Pass nitrobenzene, aniline and composite base catalyst into the reaction kettle for condensation reaction to generate condensation liquid;

[0097] The weight percent concentration of described composite base catalyst is 25%; The volume ratio of described nitrobenzene, aniline and composite base catalyst is 1:4:3;

[0098] The condensation reaction conditions are as follows: the reaction temperature is 55°C, the reaction time is 2 hours, and the reaction pressure is -0.090~-0.098MPa;

[0099] The second step is to add alkali to form a salt

[0100] Add solid caustic soda to the condensed liquid, then stir and filter to obtain a qualified condensed liquid; the stirring time for salt formation is 1 hour, and the CO in the qualified condensed liquid 3 -2 The weight percentage content is 0.1%, and the salt-forming temperature is 60°C;

...

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Abstract

The invention relates to a preparation method for p-aminodiphenylamine, and belongs to the technical field of industrial preparation for p-aminodiphenylamine. The technical problem to-be-solved is to provide a preparation method for p-aminodiphenylamine with a condensation reaction catalyst capable of being activated and reused and a reduction reaction solvent having no danger and being easily separated. The technical solution adopted includes: a first step of feeding nitrobenzene, aniline and a complex alkali catalyst into a reactor for a condensation reaction to generate a condensation liquid; a second step of adding alkali to form salt to get a qualified condensation liquid; a third step of adding soft water and composite nickel catalyst slurry, and feeding hydrogen to perform a reduction reaction to get a reduction liquid; a fourth step of extracting and distilling the reduction liquid to get a rectification raw material; and a fifth step of performing a multi-stage rectification for the rectification raw material to get the finished p-aminodiphenylamine. The method can be widely applied to the field of p-aminodiphenylamine preparation.

Description

technical field [0001] The invention discloses a preparation method of p-aminodiphenylamine and belongs to the technical field of industrial preparation of p-aminodiphenylamine. Background technique [0002] p-Aminodiphenylamine is an intermediate in the manufacture of p-phenylenediamine antioxidants and stabilizers, and is an important chemical product in the rubber and polymer industries. At present, there are mainly four industrial production methods of p-aminodiphenylamine, namely, the aniline method, the diphenylamine method, the formanilide method and the nitrobenzene method. [0003] The aniline method is simple in process and low in cost, but the reaction temperature is high, there are many side reactions, and the product quality is poor; the diphenylamine method mainly uses diphenylamine as a raw material. Higher; the formanilide method is currently the production route still used at home and abroad. This technology brings a lot of waste water and soda recovery pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/55C07C209/36C07C209/38C07C209/84
Inventor 薛志兵
Owner 山西翔宇化工有限公司
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