Method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud

A terephthalic acid, high-purity technology, used in chemical instruments and methods, carboxylate preparation, organic compound preparation, etc., can solve the problems of inability to remove, secondary pollution, and low product purity, and achieve economical and effective recovery. Use and improve efficiency

Pending Publication Date: 2021-12-24
DONGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem that the present invention solves is: the method for reclaiming the terephthalic acid in the printing and dyeing lime mud at present cannot remove some ethylene terephthalate oligomers close to the property of terephthalic acid, the product purity is not high, water Larger consumption and waste water generation and the use of organic solvents such as dimethylformamide are likely to cause secondary pollution and other problems

Method used

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  • Method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud
  • Method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud
  • Method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud

Examples

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Effect test

Embodiment 1

[0028] A method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud, comprising:

[0029] Take 10 g of printing and dyeing white mud, wash it with 30 mL of sulfuric acid solution with a concentration of 0.5 mol / L (containing 0.05 mol / L fatty alcohol polyoxyethylene ether), and centrifuge to obtain white mud filter cake; disperse the white mud filter cake in 50 mL of pure In water, use sodium hydroxide to adjust the pH to 7.0, place it in a hydrothermal kettle with a capacity of 80mL for hydrothermal reaction (150°C, 12h), and obtain the hydrothermal reaction product; centrifuge the hydrothermal product, and use an appropriate amount of pure water to dissolve The filter cake is dispersed and washed, centrifuged again to take the solid and dried to obtain a terephthalic acid product.

Embodiment 2

[0031] A method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud, comprising:

[0032] Take 10 g of printing and dyeing white mud, use 30 mL of hydrochloric acid solution with a concentration of 1.5 mol / L to wash (containing 0.05 mol / L fatty alcohol polyoxyethylene ether), and centrifuge to obtain white mud filter cake; disperse the white mud filter cake in 50 mL of pure In water, use sodium hydroxide to adjust the pH to 7.0, place it in a hydrothermal kettle with a capacity of 80mL for hydrothermal reaction (150°C, 12h), and obtain the hydrothermal reaction product; centrifuge the hydrothermal product, and use an appropriate amount of pure water to dissolve The filter cake is dispersed and washed, centrifuged again to take the solid and dried to obtain a terephthalic acid product.

Embodiment 3

[0034] A method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud, comprising:

[0035] Take 10 g of printing and dyeing white mud, wash it with 30 mL of nitric acid solution with a concentration of 1.0 mol / L (containing 0.05 mol / L fatty alcohol polyoxyethylene ether), and centrifuge to obtain white mud filter cake; disperse the white mud filter cake in 50 mL of pure In water, use sodium hydroxide to adjust the pH to 7.0, place it in a hydrothermal kettle with a capacity of 80mL for hydrothermal reaction (150°C, 12h), and obtain the hydrothermal reaction product; centrifuge the hydrothermal product, and use an appropriate amount of pure water to dissolve The filter cake is dispersed and washed, centrifuged again to take the solid and dried to obtain a terephthalic acid product.

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Abstract

The invention discloses a method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud, which belongs to the technical field of solid waste recycling in the textile printing and dyeing industry. The recovering method comprises the following steps of washing the alkali-decrement white mud by using a dilute acid solution containing a surfactant, and then carrying out solid-liquid separation to obtain a white mud filter cake, dispersing the white mud filter cake in water, adjusting the pH value, and carrying out a hydrothermal reaction in a hydrothermal kettle, carrying out solid-liquid separation on the hydrothermal product, and washing an obtained filter cake by using a proper amount of pure water, and carrying out solid-liquid separation again, taking the solid, and drying to obtain the high-purity terephthalic acid. The pure terephthalic acid recovered by the method has the impurity content of less than 1.5% and the average grain size of more than 145 microns, and can be recycled for polyester synthesis or plasticizer synthesis, so that the printing and dyeing white mud is economically and effectively recycled.

Description

technical field [0001] The invention relates to a method for hydrothermally recovering high-purity terephthalic acid from printing and dyeing white mud, and belongs to the technical field of solid waste recycling in the textile printing and dyeing industry. Background technique [0002] Printing and dyeing white mud (alkali reduction white mud) mainly comes from the alkali reduction process in the dyeing process of polyester chemical fiber fabrics. The alkali weight reduction process is an important link in the printing and dyeing production of polyester fabrics, and it is also a key pollution-producing link. It treats the polyester fabric with high temperature and relatively concentrated caustic soda, and the hydrolysis of the polyester fiber can make the fabric lighter and the fiber diameter smaller, so that the fabric feels soft and has a soft luster. The weight reduction rate of polyester fabrics is generally 5-20%. This part of waste enters the wastewater in the form o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/42C07C51/47C07C51/43C07C51/487C07C63/26
CPCC07C51/42C07C51/47C07C51/43C07C51/487C07C63/26
Inventor 李方沈忱思章耀鹏徐晨烨杜繆佳
Owner DONGHUA UNIV
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