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Method for recovering hydroxyacetate from phenoxyacetic acid pesticide wastewater

A technology of phenoxyacetic acids and glycolic esters, which is applied in the preparation of carboxylic acid esters, chemical instruments and methods, and the preparation of organic compounds, and can solve the problems of low conversion rate, high price and uneconomical industrial production. Achieve the effect of reducing waste water and simplifying the process

Inactive Publication Date: 2015-09-16
SHANGHAI TAIHE INT TRADE CO LTD +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of the first method is that the conversion rate is low, resulting in a low utilization rate of raw materials; the disadvantage of the second method is that the price of the halogenated hydrocarbon used is generally higher than that of the corresponding alcohol, and it will consume at least an equivalent amount of alkali to promote the reaction and produce new solid waste, making industrial production very uneconomical

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Wastewater Concentration

[0031] 20kg of waste water is concentrated step by step at 95 degrees (vacuum 40mmHg), and firstly concentrated until the solid content is 10% and filtered to obtain salt and concentrated solution 1, and the concentrated solution 1 is further concentrated at 95 degrees (vacuum 40mmHg) To a solid content of 10%, the salt and concentrated solution 2 were obtained by filtration, and then the concentrated solution 2 was concentrated to constant weight at 95 degrees (vacuum 40mmHg), and the salt and concentrated solution 3 (1.04kg) were obtained by filtration.

[0032] Preparation of methyl glycolate

[0033] Mix the concentrated solution 3 with 0.76 kg of benzene and 0.62 kg of methanol, add 0.1 kg of 732-type cation exchange resin, react at 70 degrees for 30 hours, cool to room temperature, and filter to obtain a reaction liquid containing methyl glycolate, methanol and benzene. Reaction liquid is carried out rectification, and reflux ratio is f...

Embodiment 2

[0041] The method for reclaiming glycolic acid ester in phenoxyacetic acid pesticide waste water, adopts the following steps:

[0042] (1) The vacuum degree of controlled decompression heating is 1mmHg, the temperature is 10°C, the vacuum degree of heating is concentrated to a solid solution ratio of 1:1, and the solid salt is removed by centrifugation, and the resulting mother liquor continues to be distilled at a vacuum degree of 1mmHg at 10°C. Water until the solid solution ratio is 1:1, centrifuge to remove the solid salt, and continue to distill the obtained mother liquor to remove water at a vacuum degree of 1mmHg at 10°C until no more water is distilled, and centrifuge to remove the solid salt to obtain glycolic acid. Yellow to reddish-brown wastewater concentrated mother liquor, wherein, the wastewater for producing phenoxyacetic acid pesticides contains 0.1% by mass of glycolic acid, 0.1% by mass of glycolic acid polymer, and 0.1% by mass of glycolic acid polymer. 1% ...

Embodiment 3

[0045] The method for reclaiming glycolic acid ester in phenoxyacetic acid pesticide waste water, adopts the following steps:

[0046] (1) Control the vacuum degree of decompression heating to 20mmHg, and the temperature is 50°C, concentrate under reduced pressure heating to a solid solution ratio of 1:6, centrifuge to remove the solid salt, and continue to distill the obtained mother liquor at a vacuum degree of 50mmHg at 80°C Water until the solid solution ratio is 1:4, centrifuge to remove the solid salt, and continue to distill the obtained mother liquor to remove water at a vacuum degree of 90mmHg at 80°C until no more water is distilled, and centrifuge to remove the solid salt to obtain glycolic acid. Yellow to reddish-brown waste water concentrated mother liquor, wherein the waste water for producing phenoxyacetic acid pesticides contains 5% glycolic acid by mass percentage, 4% glycolic acid polymer by mass percentage, and 25% of sodium chloride and 10% by mass of dichl...

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Abstract

The invention relates to a method for recovering hydroxyacetate from phenoxyacetic acid pesticide wastewater. The method comprises the following steps: carrying out concentrations desalting on wastewater for producing phenoxyacetic acid pesticides under reduced pressure heating conditions to obtain a wastewater concentrate mother liquor containing hydroxyacetic acid; and continuously reacting the wastewater concentrate mother liquor with alcohol in the presence of acidic cation exchange resin as a catalyst to obtain hydroxyacetate. Compared with the prior art, the method adopting the acidic cation exchange resin to substitute other acids as a catalyst has the advantages of technologic process simplification, reduction of the wastewater discharge amount, and recycling and reuse of the catalyst.

Description

technical field [0001] The invention belongs to the field of recycling and utilization of pesticide waste water, and in particular relates to a kind of important chemical intermediate hydroxyl group prepared from the waste water produced by the production of phenoxyacetic acid pesticides (mainly including 2,4-D and 2-methyl-4-chlorine, etc.). Acetate method. Background technique [0002] The synthesis process route of phenoxyacetic acid pesticides all goes through the condensation process of chloroacetic acid and phenol, in which the excess chloroacetic acid will be hydrolyzed to produce glycolic acid. [0003] At present, domestic manufacturers of phenoxyacetic acid pesticides will produce a large amount of waste water with high COD (mainly glycolic acid produced by hydrolysis of chloroacetic acid). The treatment of these wastewater will generate a large amount of high COD solid waste, which not only greatly increases the cost of three waste treatment, but also pollutes th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/675C07C67/08
Inventor 汪淼张照军王海波谢思勉田晓宏
Owner SHANGHAI TAIHE INT TRADE CO LTD
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