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Preparation method of diphenylamine

A technology of methoxydiphenylamine and methoxyaniline is applied in the field of preparation of 2-methyl-4-methoxydiphenylamine, and can solve the problems of limiting the industrial application of process synthesis methods, high cost and the like

Inactive Publication Date: 2017-07-14
康爱特维迅(蓬莱)化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the problem of mechanical application of catalysts in the synthesis method of this process has not been solved, resulting in high cost, which limits the industrial application of the synthesis method of this process

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Condensation reaction: Add 2400L of toluene into a 5000L reactor, add 600kg of 2-methyl-4-methoxyaniline and 822kg of o-chlorobenzoic acid under stirring. After stirring, add 152kg of caustic soda and heat to 100-120℃ for reflux The reaction was carried out for 10 hours to obtain a carboxyl group-containing diphenylamine reaction liquid.

[0033] Acidification reaction: After the condensation reaction is completed, toluene is recovered by heating and distillation. The distillation temperature is 140°C and all toluene is evaporated. Add 3m of water into the 10000L acidification kettle 3 , Then transfer the above reaction liquid to the acidification kettle, slowly add about 462kg of industrial hydrochloric acid under stirring, subject to acidification to pH=2-3. Filter, water 4m 3 Wash to neutral to obtain a wet cake. Dry the wet filter cake to obtain about 1100 kg of dry product for use.

[0034] Decarboxylation reaction: add 5000L methanol into the 10000L decarboxylation k...

Embodiment 2

[0038] Condensation reaction: Add 3000L of toluene into a 5000L reactor, add 500kg of 2-methyl-4-methoxyaniline and 807kg of o-bromobenzoic acid under stirring. After stirring, add 127kg of caustic soda and heat to 100-110℃ for reflux The reaction was carried out for 6 hours to obtain a carboxyl group-containing diphenylamine reaction liquid.

[0039] Acidification reaction: After the condensation reaction is completed, toluene is recovered by heating and distillation. The distillation temperature is 140°C and all toluene is evaporated. Add 2m of water into the 5000L acidification kettle 3 , Then transfer the above reaction liquid to the acidification kettle, and slowly add about 386kg of industrial hydrochloric acid under stirring, subject to acidification to pH=2-3. Filter, water 3m 3 Wash to neutral to obtain a wet cake. Dry the wet filter cake to obtain a dry product of about 935 kg, which is ready for use.

[0040] Decarboxylation reaction: Add 3000L methanol into the 5000L ...

Embodiment 3

[0043] Example 3 The influence of different acid binding agents on the reaction yield in the condensation reaction

[0044] The preparation process operation steps are the same as in Example 1, wherein different acid binding agents are used in the condensation step, including: (1) caustic soda; (2) potassium hydroxide; (3) sodium carbonate; (4) sodium bicarbonate. See Table 1 for the final measured total yield of the reaction.

[0045] Table 1

[0046] Group Caustic soda Potassium hydroxide Sodium carbonate Potassium Bicarbonate Yield 84.3％75.2％54.3％44.2％

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PUM

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Abstract

The invention relates to a preparation method of diphenylamine, and concretely relates to a preparation method of 2-methyl-4-methoxydiphenylamine. The method comprises the following steps: reacting an initial reaction substance 2-methyl-4-methoxyaniline with halogenated benzoic acid to obtain a carboxyl group-containing diphenylamine compound, and carrying out acidification, decarboxylation and purification to obtain the 2-methyl-4-methoxydiphenylamine.

Description

Technical field [0001] The invention relates to a method for preparing diphenylamine. Specifically, the present invention relates to a preparation method of 2-methyl-4-methoxydiphenylamine. Background technique [0002] 2-Methyl-4-methoxydiphenylamine is the key intermediate of fluoran-based black heat-sensitive couplers and can be used to synthesize heat-sensitive couplers such as ODB-1, ODB-2, S-205, etc. [0003] The traditional process for preparing 2-methyl-4-methoxydiphenylamine is based on m-cresol as the starting material, through etherification of dimethyl sulfate and bromine bromination to obtain 2-methyl-4-methoxy Bromobenzene is then condensed with acetanilide and then hydrolyzed under strong alkaline conditions to finally obtain 2-methyl-4-methoxydiphenylamine. The process route is long, the reaction is complicated, the yield is low, and there are many wastes; dimethyl sulfate is used for the etherification of m-cresol, and dimethyl sulfate is a highly toxic chemical...

Claims

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Application Information

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IPC IPC(8): C07C213/08C07C217/92
CPCC07C213/08C07C227/08C07C217/92C07C229/58
Inventor 林淑美高景庆任志惠王毅
Owner 康爱特维迅(蓬莱)化学有限公司
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