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Method for continuously preparing p-aminodiphenylamine

A technology of p-aminodiphenylamine and nitrodiphenylamine, which is applied in the field of synthesis of p-aminodiphenylamine, can solve the problems of large catalyst loss, high labor intensity, and low catalytic activity, and achieve reduced dosage, improved product quality, and high activity Effect

Inactive Publication Date: 2018-10-09
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the problems of multi-pot operation, environmental pollution, low catalytic activity, high labor intensity, and large catalyst loss in the prior art, thereby providing a method for continuously preparing p-aminodiphenylamine using a supported catalyst

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Add 50g of supported palladium-carbon catalyst with a content of 1% into the fixed bed reactor, continuously add 31.25% methanol and 68.75% aniline to the fixed bed reactor with a pump, raise the temperature to 60°C, and preheat the catalyst with a mass concentration of 15%. 4-Nitrosodiphenylamine and the above-mentioned methanol and aniline solution with a concentration of 5% 4-nitrodiphenylamine are brought to 60°C, and the above solution is added to the fixed-bed reactor with a pump, and the flow rate of the solution is adjusted to 0.2mL / min. The hydrogen pressure is 0.5 MPa, the hydrogen flow rate is 100mL / min, the reaction residence time is 200min, and the reaction materials are regularly sampled and analyzed. The conversion rate of the raw materials is 91.1%, and the selectivity is 93.2%. Distillation treatment to obtain p-aminodiphenylamine.

Embodiment 2

[0024] Add 40g of 2% supported palladium-carbon catalyst into the fixed-bed reactor, add 18.75% ethanol and 81.25% aniline to the fixed-bed reactor continuously with a pump, raise the temperature to 80°C, and preheat 4 -Nitrosodiphenylamine and the above-mentioned ethanol and aniline solution with a concentration of 10% of 4-nitrodiphenylamine to 60°C, add the above solution into the fixed-bed reactor with a pump, adjust the flow rate of the solution to 0.2mL / min, hydrogen The pressure was 1.5 MPa, the hydrogen flow rate was 50mL / min, the reaction residence time was 90min, and the reaction materials were regularly sampled and analyzed. The conversion rate of the raw materials was 94.1%, and the selectivity was 95.0%. Distillation treatment to obtain p-aminodiphenylamine.

Embodiment 3

[0026] Add 30g of supported palladium-carbon catalyst with a content of 3% to the fixed bed reactor, continuously add 50% methanol and 50% aniline to the fixed bed reactor with a pump, raise the temperature to 90°C, and preheat the catalyst with a mass concentration of 12%. 4-nitrosodiphenylamine and methanol and aniline solution with a concentration of 8% of 4-nitrodiphenylamine to 60 ° C, the above solution is added to the fixed bed reactor with a pump, and the flow rate of the solution is adjusted to 0.2mL / min, hydrogen The pressure was 2.0 MPa, the hydrogen flow rate was 40 mL / min, and the reaction residence time was 100 min. The reaction materials were regularly sampled and analyzed. The conversion rate of the raw materials was 95.1%, and the selectivity was 96.0%. Distillation treatment to obtain p-aminodiphenylamine.

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PUM

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Abstract

The invention provides a method for preparing p-aminodiphenylamine through continuous catalysis. According to the method, 4-nitrodiphenylamine and 4-nitrosodiphenylamine are used as raw materials andsubjected to continuous reduction in the presence of an organic solvent under the catalysis of a supported catalyst so as to obtain p-aminodiphenylamine. The method of the invention solves the problems of environmental pollution, low catalyst activity, difficult catalyst recovery and high labor intensity in the prior art.

Description

technical field [0001] The invention belongs to the field of organic synthesis and relates to a synthesis method of p-aminodiphenylamine. Background technique [0002] p-Aminodiphenylamine is an important organic intermediate, which is widely used in industries such as dyestuffs, textiles, printing, pharmaceuticals and rubber additives. At present, it is mainly used in the rubber additive industry as an intermediate of p-phenylenediamine rubber anti-aging agent, and is the parent body of 40-type anti-aging agent (anti-aging agent 4010, 4010NA, 6PPD and 688, etc.) with excellent performance. [0003] At present, the main methods for preparing p-aminodiphenylamine are: diphenylamine method, aniline method, formanilide method, and nitrobenzene method. Among them, the nitrobenzene method has the advantages of less three wastes and less by-products. The research hotspots mainly focus on A condensation reaction step and a catalytic hydrogenation reaction step. [0004] Hydrogena...

Claims

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Application Information

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IPC IPC(8): C07C209/36C07C209/38C07C211/51
CPCC07C209/36C07C209/38C07C211/51Y02P20/584
Inventor 丁红霞金玉存金汉强何育苗杨忠林
Owner CHINA PETROLEUM & CHEM CORP
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