Continuous flow efficient production method of 2-amino-4-nitrotoluene

A technology of nitrotoluene and production methods, which is applied in the preparation of amino compounds, chemical instruments and methods, and the preparation of organic compounds, etc., can solve the problems of reducing the risk factor of the reaction, unfavorable treatment of large amount of waste acid, and long reaction cycle, etc., to achieve Good fluidity, improved atom economy, and short reaction time

Pending Publication Date: 2022-05-13
CHANGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention aims at the problems of high risk factor, poor selectivity, many side reactions, large amount of waste acid unfavorable for treatment, environmental pollution, long reaction cycle and other problems existing in the existing production process, and innovates and improves from two aspects of production route and production equipment , to provide a continuous flow efficient production method of scarlet base G (2-amino-4-nitrotoluene)
Acylation and salt formation use acetic anhydride and acetic acid, which reduces the risk factor of the reaction. The nitration reaction uses halogenated hydrocarbon as a solvent, which has low viscosity and low risk. The solvent can be recycled and reused. A microchannel reactor is also used to solve the problem of reaction cycle and For the problem of reaction conversion rate, the hydrolysis reaction is hydrolyzed with sulfuric acid, and then neutralized with lye to further increase the reaction yield

Method used

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  • Continuous flow efficient production method of 2-amino-4-nitrotoluene
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  • Continuous flow efficient production method of 2-amino-4-nitrotoluene

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Effect test

Embodiment 1

[0032] (1) Dissolve 1 mol o-toluidine in 6 mol acetic acid, add 1 mol acetic anhydride dropwise in a stirred tank reactor for acylation reaction, control the acylation reaction temperature at 20°C, and add acetic anhydride dropwise for 1 hour , and concentrated by distillation to obtain o-methylacetanilide acetate;

[0033] (2) o-methylacetanilide acetate is dissolved in dichloromethane solvent and the 50% nitric acid solution that configures, according to o-methylacetanilide acetate / nitric acid molar ratio 1:1 feed, pump respectively Into a microchannel reactor module with a direct-flow channel and a circular cake-type pulse variable-diameter rectangular flat pipe for nitration reaction, the reaction temperature is controlled at 20°C, the residence time is 1min, and the pressure is 1bar, and the nitration liquid is collected at the end of the reactor. Dissolved in ice water, crystallized, and separated by filtration to obtain m-nitro-o-methylacetanilide acetate, and the filtr...

Embodiment 2

[0036] (1) Dissolve 1 mol of o-toluidine in 6.1 mol of acetic acid, add 1.03 mol of acetic anhydride dropwise in a stirred tank reactor for acylation reaction, control the temperature of the acylation reaction at 21°C, and the time for adding acetic anhydride For 1.1h, concentrated by distillation to obtain o-methylacetanilide acetate;

[0037](2) o-methylacetanilide acetate is dissolved in dichloroethane solvent and the 55% nitric acid solution that configures, feeds according to o-methylacetanilide acetate / nitric acid molar ratio 1:1.05, respectively Pumped into the microchannel reactor module with the structure of straight-through channel and oblique square cake pulse variable diameter rectangular flat pipe for nitrification reaction, the reaction temperature is controlled at 25°C, the residence time is 1.5min, the pressure is 2bar, and it is collected at the end of the reactor The nitration solution is dissolved in ice water, crystallized, filtered and separated to obtain ...

Embodiment 3

[0040] (1) Dissolve 1 mol of o-toluidine in 6.2 mol of acetic acid, add 1.05 mol of acetic anhydride dropwise in a stirred tank reactor for acylation reaction, control the temperature of the acylation reaction at 22°C, and the time for adding acetic anhydride For 1.2h, concentrated by distillation to obtain o-methylacetanilide acetate;

[0041] (2) Dissolve o-methylacetanilide acetate in chloroform solvent and the prepared 60% nitric acid solution, feed the material according to the o-methylacetanilide acetate / nitric acid molar ratio of 1:1.1, and pump them into the structure respectively The nitrification reaction is carried out in the microchannel reactor module of the direct-flow channel and the enhanced mixed round cake rectangular flat pipe, the reaction temperature is controlled at 30°C, the residence time is 2min, and the pressure is 3bar. The nitrification liquid is collected at the end of the reactor and passed through ice water. Dissolving, crystallizing, filtering a...

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Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a continuous flow high-efficiency production method of 2-amino-4-nitrotoluene, acetic anhydride and acetic acid are adopted for acylation salt formation, the reaction danger coefficient is reduced, halogenated hydrocarbon is used as a solvent for nitration reaction, the viscosity is small, the danger is small, the solvent can be recycled, and the production cost is low. And the problems of reaction period and reaction conversion rate are solved by adopting the micro-channel reactor, and the reaction yield is further improved by hydrolyzing with sulfuric acid and neutralizing with alkali liquor in the hydrolysis reaction. The method has the advantages of good economy, high atom utilization rate, good safety, continuous production of nitration reaction, and good industrial production prospect.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a continuous-flow high-efficiency production method of 2-amino-4-nitrotoluene. Background technique [0002] 2-Amino-4-nitrotoluene is a golden yellow crystalline solid, mainly used for dyeing and printing of cotton fabrics, coupled with naphthol AS or AS-D to dye bright red (that is, flag red), and can also be used for silk, Dyeing of viscose and nylon fabrics, also used as an intermediate of organic pigments. Regarding its synthetic method, o-toluidine is mainly used as a raw material at present, and the product is obtained by centrifugation after sulfuric acid salification, nitration, and soda ash neutralization. [0003] Patent CN 106278908 A adopts o-toluidine as raw material, 98% sulfuric acid and part of 50% sulfuric acid to form salt, mixed acid nitration reaction, and then neutralize with liquid ammonia and then centrifugally filter to obtain the product. This traditio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/62C07C211/52C07C231/12C07C233/15C07C231/02C07C233/07B01J19/00
CPCC07C209/62C07C231/12C07C231/02B01J19/0093C07C211/52C07C233/15C07C233/07
Inventor 江多镀马晓明刘建武严生虎张跃
Owner CHANGZHOU UNIV
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