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A new bromination process of 2,4-dinitroaniline

A technology of dinitroaniline and new process, applied in the field of pharmaceutical intermediates, can solve the problems of high bromine corrosiveness and toxicity, cannot meet industrial needs, and the reaction operation is cumbersome, and achieves simple operation, easy separation, and promotes the reaction to proceed. Effect

Active Publication Date: 2019-12-03
浙江汇翔新材料科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method uses bromine as the bromination agent. Bromine is highly corrosive and toxic, and it is in direct contact with the equipment during the reaction. The material requirements for the equipment are relatively high, and the reaction operation is relatively cumbersome.
[0009] Although the bromination processes such as the sodium bromide-hydrogen peroxide method and the NBS-DMF method of 2,4-dinitroaniline have been reported recently, they still cannot meet the needs of industry, and then there is an urgent need to develop a kind of 2,4-dinitroaniline The new bromination process

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0026] Weigh 36.8g of 1,4-butane sultone, add 300ml of ethyl acetate into the reactor, install a constant pressure dropping funnel, a magnetic stirrer and a reflux condenser, and heat up to 60°C in a water bath. Slowly add 24.6g of N-methylimidazole at ℃, after the dropwise addition is completed, keep the system warm at 80℃ for 2 hours until a white precipitate is produced; filter the system under reduced pressure, wash the filter cake with ethyl acetate, and put it in an oven Drying at 100°C, the resulting product is 1-methyl-3-(4-sulfonic acid) butyl imidazolium salt; add water to the 1-methyl-3-(4-sulfonic acid) butyl imidazolium salt Dissolve, add hexafluorophosphoric acid to react at 80°C, and then remove the water to obtain a light yellow viscous liquid product, which is 1-methyl-3-(4-sulfonic acid) butylimidazole hexafluorophosphate ionic liquid catalyst .

Embodiment 2

[0028] In a four-neck flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, add 150 g of tetrahydrofuran, 150 g of 30% hydrogen peroxide, 13 g of 1-methyl-3-(4-sulfonic acid) butylimidazole six Fluorophosphate, start the stirring device, drop 180g of 60% sodium bromide solution and 30.5g of 2,4-dinitroaniline at the same time under the condition of 50°C, control the dropping speed so that the two drop simultaneously within 5 hours After the heat preservation reaction was completed for about 4 hours, the temperature was raised to 60 ° C, and the temperature was maintained for 5 hours, then the temperature was raised to 90 ° C, and the temperature was maintained for 3 hours to obtain a 6-bromo-2,4-dinitroaniline solution. Separate the 1-methyl-3-(4-sulfonic acid group) butylimidazolium hexafluorophosphate ionic liquid layer and the product layer, wash the product layer with water until neutral, and drain to obtain 6-bromo-2,4-di The crude product ...

Embodiment 3

[0030] In a four-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, add 1 kg of ethyl acetate, 1 kg of 30% hydrogen peroxide, 0.2 kg of 1-methyl-3-(4-sulfonic acid) butyl imidazole hexafluorophosphate, start the stirring device, and drop 1.8kg of 50% sodium bromide solution and 0.3kg of 2,4-dinitroaniline at the same time under the condition of 50°C, and control the rate of addition so that the two are within 5 The drops were completed within 1 hour, and the temperature was raised to 60°C after the heat preservation reaction for about 4 hours, and the heat preservation was 5 hours. Set the layers, separate the 1-methyl-3-(4-sulfonic acid group) butylimidazolium hexafluorophosphate ionic liquid layer and the product layer, wash the product layer with water to neutrality, and drain to obtain 6-bromo-2 , 4-dinitroaniline crude product, add 3 times the weight of the crude product, soak in ethanol with a volume percentage concentration of 6...

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Abstract

The invention discloses a new bromination process for 2,4-dinitraniline, wherein a bromine salt such as hydrogen peroxide and sodium bromide is used as a brominating agent, and 1-methyl-3-(4-sulfonyl)butyl imidazolium hexafluorophosphate ionic liquid catalyst is added, and gradient elevation of temperature is performed in the reaction, which can effectively promote the reaction to improve reactionselectivity and catalytic reaction rate, effectively promote the reaction, and enhance yield of 6-bromine 2,4-dinitraniline. The method provided by the invention has the advantages of low cost, simple operation, safety and environmental protection, and is easy for industrialized application.

Description

technical field [0001] The invention belongs to the field of pharmaceutical intermediates, and specifically relates to a new bromination process of 2,4-dinitroaniline. Background technique [0002] 6-Bromo-2,4-dinitroaniline has a molecular formula of C6H4BrN304, a molecular weight of 26203, and a melting point of 153-154°C. Easy sublimation. Soluble in hot water and hot acetone, soluble in hot acetic acid. It can be used in the production of indigo dyes and intermediates of some acid dyes. It can make the color of the dye itself bright and improve the colorability and fastness of the dye. 6-Bromo-2,4-dinitroaniline is a fine chemical intermediate with development potential. [0003] The industrial production method of 6-bromo-2,4-dinitroaniline mainly includes the following two routes: [0004] 1) Prepared by aminolysis of 2-bromo-4,6-dinitrochloroaniline [0005] [0006] 2) Reaction of 2,4-dinitroaniline with bromine [0007] [0008] The process commonly use...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C209/74C07C211/52
CPCC07C209/74C07C211/52Y02P20/54
Inventor 阮煜翔金海
Owner 浙江汇翔新材料科技股份有限公司
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