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Preparation method for 5-chloro-2-methyl-1,4-phenylenediamine

A technology of methylaniline and phenylenediamine, which is applied in the field of preparation of chemical intermediates, can solve the problems of complex process, large gap, and many steps, and achieve the effects of high yield, low production cost, and convenient operation

Active Publication Date: 2014-01-15
ZHEJIANG DINGLONG TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

All have experienced acetylation to protect the amino group, mixed acid nitration, acid or alkaline hydrolysis to remove the protective group acetyl group, iron powder / hydrochloric acid to reduce the nitro group to the amino group, neutralization and recrystallization to prepare the product, there are complicated processes, many steps, and large pollution. The problem is that there is a big gap with the new type of industrialization that is advocated by the country today, and there is an urgent need to replace it with new routes and new processes.

Method used

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  • Preparation method for 5-chloro-2-methyl-1,4-phenylenediamine
  • Preparation method for 5-chloro-2-methyl-1,4-phenylenediamine
  • Preparation method for 5-chloro-2-methyl-1,4-phenylenediamine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Diazo coupling reduction direct method (5-chloro-2-methylaniline-o-toluidine method)

[0048] Add 42.9g of o-toluidine (OT, 0.40mol) to the hydrochloric acid aqueous solution (mass concentration: 12%) mixed with 150g of water and 100g of 30% hydrochloric acid, control the temperature at 0-5°C, and drop 112.6g of mass within 15min 25% sodium nitrite (0.408mol) aqueous solution was stirred and reacted for 15 minutes to obtain a diazotized solution of o-toluidine. This o-toluidine diazonium salt solution was added dropwise at 8-10°C to a solution containing 56.6g 5-chloro-2-methylaniline (0.40mol), 22.1g Na 2 CO 3 (0.208mol) and 460g of water in a stirred 1 L four-necked reaction flask, the dropwise addition was completed within 3 hours, the pH was controlled at 8~8.5, and the reaction was continued at 22~25°C for 1.5 hours to obtain the azo compound 4-amino - The reaction solution of 2-chloro-5-methyl-2'-methylazobenzene; the suspension after the reaction was directly t...

Embodiment 2

[0053] Diazo coupling reduction hydrogenolysis step-by-step method (5-chloro-2-methylaniline-o-toluidine method)

[0054] The reaction solution of the azo compound prepared by the same feeding and process as in Example 1 was filtered, and the wet product of the azo compound (yield 92.44%) was taken out, and was beaten and washed with 360ml of water and then filtered to obtain (4-amino-2-chloro -5-methyl-2'-methylazobenzene) wet product 127.8g (92.88g after drying, 0.358mol, purity 97.17%, yield 89.4%); add 620mL process water in proportion to the autoclave , 127.8g 4-amino-2-chloro-5-methyl-2'-methylazobenzene wet product (solid content 72.7%), 5g Raney-Ni catalyst and 80% hydrazine hydrate 50g (0.80mol) after sealing Return to the autoclave, after replacing the air with nitrogen, stir and heat up to 80°C, and carry out hydrazine hydrate reduction for 4 h at a speed of 600 to complete the hydrogenolysis reaction. With reference to the concentrated water vapor of Example 1, o-...

Embodiment 3

[0056] Diazo coupling reduction direct method (5-chloro-2-methylaniline-o-toluidine method)

[0057] Add 37.3g of aniline (0.40mol) to an aqueous solution of hydrochloric acid mixed with 150g of water and 100g of 35% hydrochloric acid, control the temperature at 0-5°C, and add 126.7g of sodium nitrite (0.45mol) with a mass concentration of 25% dropwise within 15 minutes ) aqueous solution, the diazotization solution of aniline was obtained after stirring for 1 h. Add this aniline diazotization solution dropwise at 8-10°C to a solution containing 56.6g 5-chloro-2-methylaniline (0.40mol), 28.3g Na 2 CO 3 (0.50mol) and 560g of water in a stirred 1 L four-necked reaction flask, the dropwise addition was completed within 4 hours, the pH was controlled at 8 to 8.5, and the stirring reaction was continued at 20°C for 3.5 hours to obtain the azo compound 4-amino-2- The reaction solution of chloro-5-methylazobenzene; the suspension after the reaction is directly transferred to a 2L a...

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Abstract

The invention relates to a preparation method for 5-chloro-2-methyl-1,4-phenylenediamine. 5-chloro-2-methyl aniline is used as a raw material and subjected to coupled reaction with aniline diazonium salt prepared through diazotization of an aniline substance to prepare an azo-compound; the azo-compound is subjected to hydrazine hydrate normal-pressure reduction and hydrogenolysis with the existence of a catalyst; in the later period of reduction, after the aniline substance taken off by reaction is subjected to water steaming out while reduction is performed; a methanol lysate is added to remove the catalyst so as to obtain a methanol water solution of 5-chloro-2-methyl-1,4-phenylenediamine; the obtained methanol water solution is subjected to adsorption, decoloring and edulcoration, and then after-treatment technologies of cooling crystallization, filtering, water washing, drying and the like to prepare high-purity 5-chloro-2-methyl-1,4-phenylenediamine; a mixture of the aniline substance subjected to steam distillation and recovery and water is separated and rectified, and then recycled in preparation of aniline diazonium salt. The preparation method has the characteristics of novel route, easily accessible raw material, high atom utilization ratio, conventional equipment, simple and convenient operation, little pollution, capability of realizing circular economy and the like.

Description

technical field [0001] The invention relates to a preparation method of a chemical intermediate, in particular to a preparation method of 5-chloro-2-methyl-1,4-phenylenediamine. Background technique [0002] 5-chloro-2-methyl-1,4-phenylenediamine, also known as 5-chloro-2-methyl-p-phenylenediamine, its molecular structure is shown in formula (I): [0003] [0004] (I) [0005] Because 5-chloro-2-methyl-1,4-phenylenediamine contains two p-amino groups, it is a widely used intermediate in organic synthesis, which can be used to synthesize paints, and can also be used as a new type of paint with bright color and excellent fastness. The synthesis of dyes can also be used to manufacture color developers for thermal shadow materials. It is mainly used for the synthesis of diacetoacetyl-5-chloro-2-methyl-p-phenylenediamine, as an intermediate for the synthesis of organic pigment macromolecule yellow, and as a coupling component; it can also be used as a raw material for the pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C211/52C07C209/42
Inventor 刘琛肖庆军袁光平施云龙金宁人
Owner ZHEJIANG DINGLONG TECH
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