Preparation method of 6-bromo-2, 4-dinitroaniline

Abstract

The invention provides a preparation method of 6-bromo-2, 4-dinitroaniline, which comprises the following steps: providing a reaction stock solution which takes an acid solution as a medium and also comprises a catalyst and a reaction raw material 2, 4-dinitroaniline; providing a brominating agent, wherein the brominating agent is dibromohydantoin; providing a bromination reaction, wherein a product of the bromination reaction is 6-bromo-2, 4-dinitroaniline. adding the brominating agent in batches, wherein the single addition amount does not exceed 1 / 20 of the total addition amount. According to the method, the dibromohydantoin is used as the brominating agent, the catalyst is matched to form a new synthesis route, the equipment requirement is low, the product is easy to separate and purify, the reaction is thorough and stable, the raw material conversion rate and the product yield are high, the mother liquor recycling efficiency is high, the wastewater discharge amount is reduced, and the production cost is reduced.

Description

technical field

[0001] The invention relates to the technical field of chemical synthesis, in particular to a preparation method of 6-bromo-2,4-dinitroaniline. Background technique

[0002] 6-bromo-2,4-dinitroaniline, also known as: 2-bromo-4,6-dinitroaniline, molecular formula: C 6 h 4 BrN 3 o 4 , Molecular weight: 262.02, appearance is yellow needle crystal, melting point is 153-154℃. Easy sublimation. Soluble in hot water and hot acetone, soluble in hot acetic acid. It is mainly used as an intermediate for disperse dyes, for the production of dyes and intermediates for some acid dyes, such as disperse blue 270, 264, 259, 125 and 130. The brominated dyes produced by 6-bromo-2,4-dinitroaniline are high-grade dyes, which have bright color and can improve the colorability and fastness of dyes, and have a large market capacity. 6-bromo-2,4-dinitroaniline is also a potential fine chemical intermediate.

[0003] At present, the method for industrially preparing 6-bromo-2...

Examples

Embodiment 1

[0041] A preparation method of 6-bromo-2,4-dinitroaniline, comprising the following steps:

[0042] 1) Add 17L of hydrochloric acid solution with a mass concentration of 2.5% into the reaction kettle, then add 4kg of 2,4-dinitroaniline, mix well, then add 20g of OP-10 to it, and stir at 50-55°C 1h, to obtain the reaction stock solution;

[0043] 2) Under heat preservation conditions, add bromination agent dibromohydantoin 3.2 kg in batches to the reaction stock solution, after adding, continue to incubate at 50-55 °C for bromination reaction for 30 minutes to obtain a reaction solution; the above-mentioned dibromohydantoin The batch addition operation is as follows: the single addition amount is 1 / 20 of the total addition amount, and the interval time is 1 / 20 of the total addition time, and the total addition time of dibromohydantoin is 3 hours;

[0044] 3) Cool the above reaction solution, filter it, then wash the resulting filter cake with purified water until the pH reaches ...

Embodiment 2

[0049] A preparation method of 6-bromo-2,4-dinitroaniline, comprising the following steps:

[0050] 1) In the reaction kettle, add 3L of hydrobromic acid solution with a mass concentration of 5%, then add 2,4-dinitroaniline 1kg, after mixing, add 50g tetrabutylammonium bromide wherein, at 60- Stir at 65°C for 0.5h to obtain a reaction stock solution;

[0051] 2) Under heat preservation conditions, add bromination agent dibromohydantoin 865g in batches to the reaction stock solution, after adding, continue to incubate at 60-65°C for bromination reaction for 60min to obtain a reaction solution; the above-mentioned dibromohydantoin The operation of batch addition is as follows: the single addition amount is 1 / 30 of the total addition amount, and the interval time is 1 / 30 of the total addition time, and the total addition time of dibromohydantoin is 1 hour;

[0052] 3) Cool the above reaction solution, filter it, then wash the resulting filter cake with purified water until the p...

Embodiment 3

[0057] A preparation method of 6-bromo-2,4-dinitroaniline, comprising the following steps:

[0058] 1) Add 5L of mixed acid solution with a mass concentration of 5% into the reaction kettle, then add 1.5kg of 2,4-dinitroaniline, mix well, then add 50g of OP-10 to it, at 55-60°C Stir for 1.5 h to obtain the reaction stock solution; the above-mentioned mixed acid solution is obtained by mixing hydrochloric acid solution and hydrobromic acid solution with a mass concentration of 5%, and its volume ratio is 1:1.5;

[0059] 2) Under heat preservation conditions, add bromination agent dibromohydantoin 1.4 kg in batches to the reaction stock solution, after adding, continue to incubate at 55-60° C. for bromination reaction for 45 minutes to obtain a reaction solution; the above-mentioned dibromohydantoin Because the operation of adding in batches is as follows: the single addition amount is 1 / 25 of the total addition amount, and the interval time is 1 / 25 of the total addition time, a...

technical field

[0001] The invention relates to the technical field of chemical synthesis, in particular to a preparation method of 6-bromo-2,4-dinitroaniline. Background technique

[0002] 6-bromo-2,4-dinitroaniline, also known as: 2-bromo-4,6-dinitroaniline, molecular formula: C 6 h 4 BrN 3 o 4 , Molecular weight: 262.02, appearance is yellow needle crystal, melting point is 153-154℃. Easy sublimation. Soluble in hot water and hot acetone, soluble in hot acetic acid. It is mainly used as an intermediate for disperse dyes, for the production of dyes and intermediates for some acid dyes, such as disperse blue 270, 264, 259, 125 and 130. The brominated dyes produced by 6-bromo-2,4-dinitroaniline are high-grade dyes, which have bright color and can improve the colorability and fastness of dyes, and have a large market capacity. 6-bromo-2,4-dinitroaniline is also a potential fine chemical intermediate.

[0003] At present, the method for industrially preparing 6-bromo-2...

Examples

Embodiment 1

[0041] A preparation method of 6-bromo-2,4-dinitroaniline, comprising the following steps:

[0042] 1) Add 17L of hydrochloric acid solution with a mass concentration of 2.5% into the reaction kettle, then add 4kg of 2,4-dinitroaniline, mix well, then add 20g of OP-10 to it, and stir at 50-55°C 1h, to obtain the reaction stock solution;

[0043] 2) Under heat preservation conditions, add bromination agent dibromohydantoin 3.2 kg in batches to the reaction stock solution, after adding, continue to incubate at 50-55 °C for bromination reaction for 30 minutes to obtain a reaction solution; the above-mentioned dibromohydantoin The batch addition operation is as follows: the single addition amount is 1 / 20 of the total addition amount, and the interval time is 1 / 20 of the total addition time, and the total addition time of dibromohydantoin is 3 hours;

[0044] 3) Cool the above reaction solution, filter it, then wash the resulting filter cake with purified water until the pH reaches ...

Embodiment 2

[0049] A preparation method of 6-bromo-2,4-dinitroaniline, comprising the following steps:

[0050] 1) In the reaction kettle, add 3L of hydrobromic acid solution with a mass concentration of 5%, then add 2,4-dinitroaniline 1kg, after mixing, add 50g tetrabutylammonium bromide wherein, at 60- Stir at 65°C for 0.5h to obtain a reaction stock solution;

[0051] 2) Under heat preservation conditions, add bromination agent dibromohydantoin 865g in batches to the reaction stock solution, after adding, continue to incubate at 60-65°C for bromination reaction for 60min to obtain a reaction solution; the above-mentioned dibromohydantoin The operation of batch addition is as follows: the single addition amount is 1 / 30 of the total addition amount, and the interval time is 1 / 30 of the total addition time, and the total addition time of dibromohydantoin is 1 hour;

[0052] 3) Cool the above reaction solution, filter it, then wash the resulting filter cake with purified water until the p...

Embodiment 3

[0057] A preparation method of 6-bromo-2,4-dinitroaniline, comprising the following steps:

[0058] 1) Add 5L of mixed acid solution with a mass concentration of 5% into the reaction kettle, then add 1.5kg of 2,4-dinitroaniline, mix well, then add 50g of OP-10 to it, at 55-60°C Stir for 1.5 h to obtain the reaction stock solution; the above-mentioned mixed acid solution is obtained by mixing hydrochloric acid solution and hydrobromic acid solution with a mass concentration of 5%, and its volume ratio is 1:1.5;

[0059] 2) Under heat preservation conditions, add bromination agent dibromohydantoin 1.4 kg in batches to the reaction stock solution, after adding, continue to incubate at 55-60° C. for bromination reaction for 45 minutes to obtain a reaction solution; the above-mentioned dibromohydantoin Because the operation of adding in batches is as follows: the single addition amount is 1 / 25 of the total addition amount, and the interval time is 1 / 25 of the total addition time, a...

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