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Technique for purifying crude terephthalic acid from alkali deweighting wastewater

A technology for crude terephthalic acid and alkali reduction waste water, which is applied in the field of crude terephthalic acid purification process, and can solve the problem that there is no good method for recrystallization of terephthalic acid

Active Publication Date: 2009-08-12
POTEN ENVIRONMENT GRP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The prior art does not have a good method for the recrystallization of terephthalic acid

Method used

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  • Technique for purifying crude terephthalic acid from alkali deweighting wastewater
  • Technique for purifying crude terephthalic acid from alkali deweighting wastewater
  • Technique for purifying crude terephthalic acid from alkali deweighting wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Crude terephthalic acid purification process for general purity requirements

[0039] The crude terephthalic acid recovered by membrane integrated treatment technology is dissolved in water under the condition of excessive NaOH, and the pH is controlled at 12 to 14. Under the premise of stirring, 1% of the mass of crude terephthalic acid is added in benzene, and then heated , keep the temperature of the crude terephthalic acid alkali solution between 80°C and 120°C, then add 5% hydrogen peroxide (mass percentage concentration of 10%) of the crude terephthalic acid mass, and continue stirring for 3-5 hours for hydrolysis , stop stirring, cool to 30-50°C, then filter the impurities, collect the filtrated liquid, and perform ultrafiltration to remove water-soluble macromolecular impurities.

[0040] Add dilute sulfuric acid solution for neutralization, so that the terephthalic acid in the solution is slowly acid-precipitated from the liquid phase, and the pH value is contr...

Embodiment 2

[0042] Refining Process of High Purity Terephthalic Acid

[0043] The crude terephthalic acid recovered by membrane integrated treatment technology is dissolved in water under the condition of excessive NaOH, and the pH is controlled at 12 to 14. Under the premise of stirring, 0.5-1.5% of the mass of crude terephthalic acid is added with N- Sodium oleoyl polypeptide, then heated to keep the temperature of the crude terephthalic acid alkali solution between 80°C and 120°C, then add 5% hydrogen peroxide (mass percentage concentration is 10% ), continue to stir and hydrolyze for 3-5 hours, stop stirring, cool to 30-50°C, then filter the impurities, collect the filtered clear liquid, and the filtered clear liquid can be filtered by ultrafiltration or nanofiltration according to requirements to further remove the dissolved Oligomer molecules, oligomer decomposers, etc. in serum.

[0044] Remove the clear liquid of oligomer molecules through membrane filtration. If the concentratio...

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Abstract

The invention discloses a technique for purifying crude terephthalic acid recovered from alkali weight-reduction wastewater; the crude terephthalic acid which is recovered from alkali weight-reduction wastewater is dissolved in the water under the condition of excessive sodium hudroxide, the pH value is maintained to be 12-14, and the obtained water solution is added with anion active agent or swelling agent to be heated, then added with oxidizing agent to be continuously stirred for hydrolyzation, cooled and filtered to remove solid impurity; after membrane filtration, clear solution is collected; the clear solution is slowly added with diluted acid solution for acid out and complete precipitation; the product is pressed and filtered after ultrasonic cleaning and precipitating, and filter mass is obtained; the filter mass is dried in vacuum to obtain pure dry material; the purity of the product can be further improved by repeatedly evaporating and concentrating the clear water obtained by membrane filtration and processing the dissolved crystal by membrane filtration for a plurality of times. The pure terephthalic acid prepared by the technique has the weight content of impurity to be less than 1.5%, can be used for synthesizing polyester in a circulating way and applied for the synthesis and utilization of plasticizing agent.

Description

technical field [0001] The invention relates to a purification process of crude terephthalic acid recovered from alkali reduction waste water, in particular to an integrated treatment technology of alkali reduction waste water in the alkali reduction process of polyester textile processing through membrane method, which is obtained after acid analysis Repurification technology of crude terephthalic acid. Background technique [0002] Most of the alkali reduction wastewater in the printing and dyeing industry is produced by the alkali reduction treatment process of polyester imitation silk. During the soaking process of polyester fabrics and other fabrics in a strong alkali aqueous solution at about 100 ° C, with the help of swelling agents, accelerators, surfactants, etc. The synergistic effect of the polyester (polyethylene terephthalate) macromolecular chain on the polyester fabric breaks and hydrolyzes in the hot alkali aqueous solution, falls off from the polyester fabri...

Claims

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Application Information

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IPC IPC(8): C07C63/26C07C51/42C07C51/47
Inventor 陈欢林张亚涛张林程丽华郦青
Owner POTEN ENVIRONMENT GRP
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