Method for recycling esterification acid wastewater produced in ethyl cyanoacetate production

A technology of cyanoacetate and acidic wastewater, applied in chemical instruments and methods, multi-stage water treatment, water/sewage treatment, etc., can solve problems such as complex mixed salt composition, low market demand, secondary pollution, etc. Achieve the effects of good processing effect, filling the gap in the industry, and strong applicability

Active Publication Date: 2016-04-20
HEBEI JIUTIAN MEDICINE CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existing problem is that the composition of the mixed salt is complex, the market demand is extremely small, causing secondary pollution, and the problem cannot be effectively solved

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A method for recycling acidic waste water from esterification in cyanoacetate production, comprising the steps of:

[0029] In 500g of acidic wastewater, slowly add 10g of solid sodium hydroxide to adjust the pH of the wastewater to 11, convert all the sulfuric acid and acid salts in the wastewater into sodium sulfate, and then deammoniate at 50°C for 4 hours to obtain 8g of ammonia water with a purity of 20%. Then add 2.5 g of activated carbon, decolorize at 80° C. for 10 minutes, and filter to obtain a light yellow transparent solution. Then the temperature was lowered to 0°C, sodium sulfate decahydrate crystals were precipitated and filtered to obtain 75 g of sodium sulfate decahydrate solid with a purity of 95.6%. The remaining filtrate was vacuum dehydrated and concentrated to a solid-to-liquid volume ratio of 1:1, then filtered to obtain 60 g of sodium chloride solid with a purity of 98%. The remaining cyanoacetate solution is 60g, with a purity of 9.5%. After d...

Embodiment 2

[0031] A method for recycling acidic waste water from esterification in cyanoacetate production, comprising the steps of:

[0032] Slowly add 30g of liquid sodium hydroxide (30% sodium hydroxide aqueous solution) to 500g of acidic wastewater to adjust the pH of the wastewater to 12, convert all the sulfuric acid and acid salts in the wastewater into sodium sulfate, and then deammoniate at 20°C After 6 hours, 8 g of aqueous ammonia was produced with a purity of 20%. Then add 0.05 g of activated carbon, decolorize at 20° C. for 60 minutes, and filter to obtain a light yellow transparent solution. Then the temperature was lowered to -5°C, sodium sulfate decahydrate crystallized and filtered to obtain 75 g of sodium sulfate decahydrate solid with a purity of 96%. The remaining filtrate was vacuum dehydrated and concentrated to a solid-to-liquid volume ratio of 1:0.8, then filtered to obtain 60 g of sodium chloride solid with a purity of 97%. The remaining cyanoacetate solution i...

Embodiment 3

[0034] A method for recycling acidic waste water from esterification in cyanoacetate production, comprising the steps of:

[0035] In 1000g of acidic wastewater, slowly add 20g of solid sodium hydroxide to adjust the pH of the wastewater to 11, convert all the sulfuric acid and acid salts in the wastewater into sodium sulfate, and then deammoniate at 80°C for 1 hour to obtain 16g of ammonia water with a purity of 20%. Then add 1 g of activated carbon, decolorize at 50° C. for 40 minutes, and filter to obtain a light yellow transparent solution. Then the temperature was lowered to 0°C, sodium sulfate decahydrate crystallized and filtered to obtain 150 g of sodium sulfate decahydrate as a solid with a purity of 96.5%. The remaining filtrate was vacuum dehydrated and concentrated to a solid-to-liquid volume ratio of 1:1.2, then filtered to obtain 120 g of sodium chloride solid with a purity of 97%. The remaining cyanoacetate solution was 120g, with a purity of 9.8%, and 614g of...

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PUM

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Abstract

The invention discloses a method for recycling esterification acid wastewater produced in ethyl cyanoacetate production, and relates to the technical field of ethyl cyanoacetate production. The method comprises the following steps: (1) adding sodium hydroxide into wastewater, totally transforming sulfuric acid and acidic salt in the wastewater into sodium sulfate, performing ammonia removal treatment to release ammonia gas, and absorbing the ammonia gas with water to obtain ammonia water; (2) decolorizing the ammonia-removed wastewater to obtain a light-colored transparent solution; (3) cooling the decolorized wastewater to be below 0 DEG C, and filtering to obtain a sodium sulfate crystalline solid; (4) dehydrating and concentrating filtrate, and filtering to obtain a sodium chloride solid, wherein residual mother liquor is an ethyl cyanoacetate solution which is recycled for production. The method is simple, and has high adaptability and a good treatment effect; by adopting the method, components in the wastewater can be transformed, and a high-purity byproduct can be separated and purified or recycled, so that recycling is realized, secondary pollution is avoided, industrial problems are solved, and the industrial blank is filled up.

Description

technical field [0001] The invention relates to the technical field of cyanoacetate production. Background technique [0002] Cyanoacetate, also known as cyanoacetate, is produced by the esterification reaction of cyanoacetic acid and corresponding alcohol under the catalysis of sulfuric acid. In the actual production process, the acid wastewater produced by esterification often contains various components such as cyanoacetate, sodium chloride, sodium bisulfate, ammonium bisulfate and sulfuric acid, and the color is dark. At present, domestic cyanoacetate production enterprises all produce a certain amount of this waste water, and for the treatment of this waste water, there are no related data reports. [0003] Most of the existing production enterprises make waste water into mixed salt. The existing problem is that the composition of the mixed salt is complex, the market demand is extremely small, and secondary pollution is caused, so the problem cannot be effectively so...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/08C01D3/04C02F103/36
CPCC01D3/04C02F1/20C02F1/22C02F1/281C02F1/66C02F9/00C02F2101/16C02F2103/36C02F2301/08
Inventor 张影宋香哲韩永晓程雪莲周进辉张国栋
Owner HEBEI JIUTIAN MEDICINE CHEM CO LTD
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