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Environment-friendly clean production method of high-purity glycolic acid

A high-purity glycolic acid, clean production technology, applied in general water supply conservation, separation/purification of carboxylic acid compounds, chemical industry, etc. Concentration requirements, improving single-pass yield, and reducing the effect of concentration difference osmosis

Inactive Publication Date: 2020-07-10
高春燕
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is clean in process, but there are the following problems: in order to ensure that there is less free ammonium sulfate in the feed liquid after adding ethanol for salt precipitation, the amount of ethanol that needs to be added is very large, reaching 5-10 times the theoretical molar amount of glycolic acid. The dehydration of ethanol and ethanol consumes a lot of energy; after the salt is separated and the solid ammonium sulfate is separated, the feed liquid still contains a certain amount of free ammonium sulfate, which affects the refined quality of the product; only 99% pure glycolic acid can be obtained, and it is difficult to produce more than 99.5% High-purity glycolic acid; the added inhibitor increases the impurity content in the product
This method has a clean process, but requires the use of hydroxyacetonitrile with a concentration of 50%, which has high requirements on raw materials, and also has the problems of large amount of isopropanol, high energy consumption, and incomplete separation of ammonium sulfate, and only 99% pure glycolic acid can be obtained. , it is difficult to produce high-purity glycolic acid with a purity of more than 99.5%

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  • Environment-friendly clean production method of high-purity glycolic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Example 1: 191kg of sulfuric acid with a concentration of 90wt% was added to the reaction kettle, and 312.5kg of hydroxyacetonitrile with a concentration of 40% was slowly added dropwise to carry out acidolysis reaction. And the acid solution of ammonium sulfate acid salt. After the acidolysis solution was cooled to normal temperature, 18 wt% ammonia water was added with stirring until the pH value of the reaction solution was 2.0 to obtain a neutralization solution.

[0046] Slowly add the ethanol of concentration 96wt% in the neutralization liquid to carry out salt analysis, the ethanol addition is 1.1 times of the water yield in the neutralization liquid, filter and separate the ammonium sulfate solid to obtain the filtrate, add the filtrate amount after the water dilution of 0.2 times of glycolic acid amount is 605.1kg (containing 27.34wt% of glycolic acid, 2.55wt% of ammonium sulfate, 36.64% of water, and 32.92% of ethanol); the ammonium sulfate solid was washed wi...

Embodiment 2

[0048] Embodiment 2: Add 217.3kg of sulfuric acid of 80wt% concentration in the reaction kettle, slowly dropwise add 310.7kg of hydroxyacetonitrile with a concentration of 35% to carry out acidolysis reaction, after the dropwise addition, heat preservation reaction at 95~105°C for 6.5h to obtain Acid hydrolyzate of glycolic acid and ammonium sulfate acid salt. After the acidolysis solution was cooled to normal temperature, 23 wt% ammonia water was added with stirring until the pH value of the reaction solution was 3.8 to obtain a neutralization solution.

[0049] Slowly add tert-butanol with a concentration of 85wt% to the neutralization solution to carry out salt precipitation. The mass of tert-butanol added is 0.7 times the amount of water in the neutralization solution, and the solid ammonium sulfate is filtered to obtain the filtrate, which is diluted with water of 0.15 times the amount of glycolic acid The amount of filtrate is 584.7kg (containing 24.66wt% of glycolic aci...

Embodiment 3

[0051] Embodiment 3: same as embodiment 2, hydroxyacetonitrile and sulfuric acid are neutralized after acidolysis to obtain a neutralization solution, and slowly add n-propanol with a concentration of 70wt% in the neutralization solution to carry out salt precipitation, and the quality of n-propanol added is the neutralization solution 0.7 times the amount of water in the middle, filter and separate the ammonium sulfate solid to obtain the filtrate, add 0.35 times the amount of glycolic acid to dilute the amount of the filtrate after water dilution is 561.0kg (containing glycolic acid 21.81wt%, ammonium sulfate 3.18wt%, water 51.14%, n-propyl Alcohol 23.39%); wash the ammonium sulfate solid with an appropriate amount of n-propanol, and apply the lotion to remove salt; dry the wet ammonium sulfate to obtain by-product ammonium sulfate, condense and recover the n-propanol in the exhaust gas to remove salt. Add modified zeolite molecular sieve to the filtrate for decolorization an...

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Abstract

The invention relates to a production method of high-purity glycolic acid, which comprises the following steps: carrying out sulfuric acid acidolysis on glycolonitrile, adding ammonia or ammonium carbonate to neutralize to obtain an aqueous solution containing glycolic acid and ammonium sulfate, carrying out alcohol precipitation, electrodialysis and other desalination treatments, concentrating, carrying out solid-liquid separation, and drying to obtain the high-purity glycolic acid. According to the method disclosed by the invention, high desalination of the aqueous solution of glycolic acidis realized through a treatment mode of combining salting-out by a salting-out agent, electrodialysis and the like, and a high-purity solid glycolic acid product with the main content of 99.5% or above can be prepared. The whole process is energy-saving, environment-friendly and clean, and is a high-purity glycolic acid environment-friendly and clean production route with practical value.

Description

technical field [0001] The invention relates to a production method for preparing high-purity glycolic acid by using hydroxyacetonitrile as a raw material through acid hydrolysis, and belongs to the field of fine chemical intermediates. Background technique [0002] Glycolic acid HOCH 2 COOH is an important fine chemical intermediate, which is widely used in chemical synthesis, medicine, spices, chemical cleaning, daily chemical industry, new biodegradable materials and fungicides. The aqueous solution of glycolic acid is a degradable and environmentally friendly cleaning agent in the field of chemical cleaning. In recent years, with the application and development of polyglycolic acid, a new biodegradable material synthesized from glycolic acid, and polylactic acid-glycolic acid in clinical surgical stents and sutures, and degradable materials for beverage packaging, the demand for high-purity glycolic acid products is also increasing. bigger and bigger. [0003] The met...

Claims

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Application Information

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IPC IPC(8): C07C51/08C07C51/47C07C59/06B01D61/52
CPCB01D61/52C07C51/08C07C51/47C07C59/06Y02P20/10Y02A20/124
Inventor 高春燕其他发明人请求不公开姓名
Owner 高春燕
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