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Method for preparing 2,4-dinitroaniline diazonium salt

A technology of dinitroaniline and diazonium salt, which is applied in the field of intermediate preparation of synthetic dyes, can solve problems such as decline, decomposition and explosion, dangerous product quality, etc. Effect

Inactive Publication Date: 2010-01-06
TIANJIN DEK CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

2,4-Dinitroaniline diazonium salt is very soluble in water, even in the presence of a large amount of sulfuric acid, it is difficult to separate from water, and after dehydration and drying, the diazonium salt is easy to cause decomposition and Explosion, which will bring danger to the production process or cause the quality of the product to decline

Method used

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  • Method for preparing 2,4-dinitroaniline diazonium salt
  • Method for preparing 2,4-dinitroaniline diazonium salt

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Diazotization: Take 135.3g of anhydrous sulfuric acid and slowly add dried NaNO at a temperature of 25°C 2 11.2g, reacted at 80°C for 2 hours. Cool down to below 40°C, then add 28g of 2,4-dinitroaniline with a content of 98% at 40°C, react for 6 hours, cool down to 10°C, dilute into ice-water mixture, control the temperature to ≤0°C, and obtain 2, 4-Dinitroaniline diazonium sulfuric acid aqueous solution.

[0027] (2) Crystallization: In 2,4-dinitroaniline diazonium salt sulfuric acid aqueous solution, add 50g of benzenesulfonic acid, stir and precipitate for more than 2 hours, filter to get 2,4-dinitroaniline diazonium salt filter cake , to dry.

[0028] (3) Drying: Dry the filter cake of 2,4-dinitroaniline diazonium salt at about 80°C to obtain powdery 2,4-dinitroaniline diazonium salt, that is, the weight of 2,4-dinitroaniline Nitrogen salt solid powder.

Embodiment 2

[0030] (1) Diazotization: take 93.7g of 98% sulfuric acid, and mix it with 41.6g containing SO under cooling 3 20% oleum was mixed to make 135.3g of anhydrous sulfuric acid. In the anhydrous sulfuric acid, slowly add dried NaNO at a temperature ≤30°C 2 11.2g, reacted at 60°C for 3 hours. Cool down to below 40°C, then add 28g of 2,4-dinitroaniline with a content of 98% at 45°C, react for 7 hours, cool down to below 15°C, dilute into ice-water mixture, control the temperature to ≤0°C, and obtain 2 , 4-Dinitroaniline diazonium sulfuric acid aqueous solution.

[0031] (2) Crystallization: In 2,4-dinitroaniline diazonium salt sulfuric acid aqueous solution, add 30g of 1,5-naphthalene disulfonic acid and 20g sodium dodecylsulfonate, stir and precipitate for more than 2 hours, filter Afterwards, the filter cake of 2,4-dinitroaniline diazonium salt was obtained and dried.

[0032] (3) Drying: Dry the filter cake of 2,4-dinitroaniline diazonium salt at 85°C to obtain powdery 2,4-di...

Embodiment 3

[0034] (1) Diazotization: take 93.7g of 98% sulfuric acid, and mix it with 41.6g containing SO under cooling 3 20% oleum was mixed to make 135.3g of anhydrous sulfuric acid. In the anhydrous sulfuric acid, slowly add dried NaNO at a temperature ≤30°C 2 11.2g, reacted at 70°C for 2 hours. Cool down to below 40°C, then add 28g of 2,4-dinitroaniline with a content of 98% at 35°C, react 8, cool down to below 15°C, dilute into ice-water mixture, control the temperature to ≤0°C, and obtain 2, 4-Dinitroaniline diazonium sulfuric acid aqueous solution.

[0035] (2) Crystallization: Add 50 g of anthraquinone-2,5-disulfonic acid to 2,4-dinitroaniline diazonium sulfuric acid aqueous solution, stir and precipitate for more than 2 hours. Filter cake of 2,4-dinitroaniline diazonium salt and wait for drying.

[0036] (3) Drying: Dry the filter cake of 2,4-dinitroaniline diazonium salt below 75°C to obtain powdery 2,4-dinitroaniline diazonium salt, that is, the weight of 2,4-dinitroanilin...

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Abstract

The invention provides a method for preparing 2,4-dinitroaniline diazonium salt. The method comprises the following steps: (1) diazotization: slowly adding dry NaNO2 to anhydrous sulfuric acid, then adding 2,4-nitroaniline, cooling the solution after a reaction and diluting the solution in a mixture of ice and water to obtain a sulfuric acid aqueous solution of the 2,4-dinitroaniline diazonium salt; (2) crystal separation: adding an anionic organic compound to the sulfuric acid aqueous solution of the 2,4-dinitroaniline diazonium salt; stirring the solution to crystallize and separate; filtering crystals to obtain a filter cake of the 2,4-dinitroaniline diazonium salt; and (3) drying: drying the filter cake of the 2,4-dinitroaniline diazonium salt to obtain 2,4-dinitroaniline diazonium salt powder, i.e. solid 2,4-dinitroaniline diazonium salt powder.

Description

technical field [0001] The invention belongs to the field of intermediate preparation of synthetic dyes, and in particular relates to a preparation method of 2,4-dinitroaniline diazonium salt solid powder. The diazonium salt is mainly used for synthesizing azo dyes. Background technique [0002] When synthesizing azo dyes, the problem of diazotization of 2,4-dinitroaniline is often encountered, such as C.I. Reactive Black 52. Diazotization of 2,4-dinitroaniline is difficult to use conventional diazotization methods The reaction must be carried out in concentrated sulfuric acid, so that after the coupling reaction, a large amount of sulfates will be produced. These sulfates will reduce the solubility of the dye, and will also affect the dyeing rate and color fastness of the dyed protein fiber and reduce it. , so if most of the sulfuric acid in 2,4-dinitroaniline diazonium salt can be removed, it will be very beneficial to the synthesis of dyes. 2,4-Dinitroaniline diazonium s...

Claims

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Application Information

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IPC IPC(8): C07C245/20
Inventor 张兴华邢广文
Owner TIANJIN DEK CHEM
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