Efficient recrystallization method of tetraacetylethylenediamine

A technology of tetraacetylethylenediamine and recrystallization, which is applied in the separation/purification of carboxylic acid amides, organic chemistry and other directions, can solve the problems of reducing the yield of TAED, large solvent loss, and high energy consumption, and achieves excellent adsorption capacity and recrystallization. High efficiency, avoids the effect of hydrolysis

Active Publication Date: 2015-04-01
ZHEJIANG JINKE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The mother liquor of this method needs to be distilled after being recycled for 2-4 times, and then applied mechanically. After the distillation, TAED remains in the residue, and the recovery solvent no longer contains TAED, so some TAED will be dissolved in the recrystallization process. In the solvent, it cannot be separated out at room temperature, resulting in low yield. The average yield of recrystallization from the mother liquor is below 93.86%. In addition, the energy consumption is high and the solvent loss is large.
In addition, during the recrystallization process, there is a certain degree of hydrolysis of tetraacetylethylenediamine, which further reduces the yield of TAED.

Method used

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  • Efficient recrystallization method of tetraacetylethylenediamine

Examples

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Effect test

Embodiment 1

[0017] 700g of tetraacetylethylenediamine, the Lab values ​​are 85.3, 0.38, 8.86 respectively, and the purity is 99.2%. 1000g of acetic acid was used as solvent. Acetic anhydride is used as a hydrolysis inhibitor, and the dosage of acetic anhydride is 50g, which is equivalent to 5% of the mass of acetic acid. The mixture of activated carbon and activated clay with a mass ratio of 1:1 is used as a decolorizing agent, and the dosage is 35g, which is equivalent to 5% of the mass of tetraacetylethylenediamine.

[0018] The above-mentioned substances were placed in a container, heated and stirred to a temperature of 80° C., and stirred and adsorbed for 30 minutes. The recrystallization system is filtered hot, the filtrate is cooled to 25°C with heat exchange and stirring, and then the solid and liquid are separated. The separated liquid is used as the mother liquor, and the solid is washed and dried to recrystallize tetraacetylethylenediamine. HLPC is used to detect the purity, ...

Embodiment 2

[0023] 500g of tetraacetylethylenediamine, the Lab values ​​are 85.3, 0.38, 8.86 respectively, and the purity is 99.2%; 1000g of acetic acid is used as a solvent; acetic anhydride is used as a hydrolysis inhibitor, and the dosage is 100g, which is equivalent to 10% of the mass of acetic acid. Activated carbon is used as a decolorizing agent in an amount of 50 g, which is equivalent to 10% of the quality of tetraacetylethylenediamine. The above-mentioned substances were placed in a container, heated and stirred to a temperature of 90° C., and stirred and adsorbed for 120 minutes. The recrystallization system is filtered hot, the filtrate is cooled to 25°C with heat exchange and stirring, and then the solid and liquid are separated. The separated liquid is used as the mother liquor, and the solid is washed and dried to recrystallize tetraacetylethylenediamine. HLPC is used to detect the purity, and the Lab mode is used to detect the color.

[0024] Heat the above mother liquor...

Embodiment 3

[0028] 100g of tetraacetylethylenediamine, the Lab values ​​are 85.3, 0.38, 8.86, and the purity is 99.2%; 1000g of acetic acid is used as a solvent; acetic anhydride is used as a hydrolysis inhibitor, and the dosage is 1g, which is equivalent to 0.1% of the mass of acetic acid. Activated clay is used as a decolorizing agent in an amount of 0.5 g, which is equivalent to 0.5% of the quality of tetraacetylethylenediamine. The above-mentioned substances were placed in a container, heated and stirred to a temperature of 60° C., and stirred and adsorbed for 5 minutes. The recrystallization system is filtered hot, the filtrate is cooled to 25°C with heat exchange and stirring, and then the solid and liquid are separated. The separated liquid is used as the mother liquor, and the solid is washed and dried to recrystallize tetraacetylethylenediamine. HLPC is used to detect the purity, and the Lab mode is used to detect the color.

[0029] Heat the above mother liquor to 100°C, add 1...

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Abstract

The invention discloses an efficient recrystallization method of tetraacetylethylenediamine, which is characterized by comprising the following steps of: a) putting acetic acid as a solvent, acetic anhydride as a hydrolysis suppressor and active carbon and / or active clay as a decoloring agent and tetraacetylethylenediamine in a container and heating to 60-90 DEG C and stirring, stirring and adsorbing for 1-120 minutes, and filtering; b) performing heat exchange stirring of the obtained filtrate and cooling to normal temperature, performing solid-liquid separation after the tetraacetylethylenediamine crystal is separated, washing the obtained solid, and drying to obtain recrystallized tetraacetylethylenediamine; and c) heating the separated liquid to 70-115 DEG C, adding polyphosphoric acid and halogen anionic alkali metal salt, mixing uniformly, enabling the mixed liquid to sufficiently contact with metal zinc, and supplementing acetic anhydride to the separated liquid as recrystallization mother liquid for cycle use. By adopting the method disclosed by the invention, a tetraacetylethylenediamine product with high yield and good quality can be obtained, and the recrystallization mother liquid can be used repeatedly.

Description

technical field [0001] The invention belongs to the technical field of purification of chemical products, and relates to a high-efficiency recrystallization method of tetraacetylethylenediamine, which is particularly suitable for the purification of tetraacetylethylenediamine products with relatively high pigment content. Background technique [0002] As an effective bleach activator, tetraacetylethylenediamine (TAED) has excellent low-temperature bleaching performance and good environmental protection, and is currently widely used in domestic and foreign washing industries. [0003] Generally, tetraacetylethylenediamine is diacylated by acetic acid and ethylenediamine, dehydrated at high temperature to form diacetylethylenediamine, and then synthesized by tetraacylation of acetic anhydride and diacetylethylenediamine. After the synthesis, the system is crystallized, filtered, washed, dried, granulated, and packaged to become a finished product of tetraacetylethylenediamine....

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C233/91C07C231/24
Inventor 施孟华芦鸿武宋盘龙
Owner ZHEJIANG JINKE CHEM
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