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Method for preparing solid glycolic acid

A technology of glycolic acid and glycolic acid, which is applied in the field of glycolic acid preparation, can solve the problems of low extraction rate, complex process, and slow extraction speed, and achieve high yield, high purity, and simple operation

Inactive Publication Date: 2017-04-26
SHAANXI YIPINDA PETROCHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because this method uses a large amount of organic solvents, and it is dangerous, and the extraction speed is slow, the product extraction rate is low, and it takes a long time. It is not suitable for production and use. The process is complicated and requires many equipment. In addition, the concentration takes a long time, resulting in more lactide in the final solid glycolic acid, which affects the quality of the final glycolic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A method for preparing solid glycolic acid, comprising the following steps:

[0019] (1) Hydrolysis reaction of glycolic acid: Add 15mL of concentrated sulfuric acid and 50mL of water into a flask equipped with a thermometer, mechanical stirring, dropping funnel, and reflux condenser, and add 100mL of hydroxyacetonitrile aqueous solution dropwise under stirring. Insulate at -60°C for 4 hours, cool to room temperature, and obtain an aqueous solution of glycolic acid and ammonium bisulfate;

[0020] (2) Neutralization reaction: Add concentrated ammonia water to carry out neutralization reaction under stirring until the pH of the reaction system is 6.5;

[0021] (3) Desalination: add 300mL of anhydrous isopropanol to the product of step (2), stir at room temperature for 0.5 hours, filter with suction, dry the filter cake obtained by suction filtration, recover the filtrate, add 5g of charcoal for injection to decolorize After obtaining a colorless transparent liquid;

[...

Embodiment 2

[0025] A method for preparing solid glycolic acid, comprising the following steps:

[0026] (1) Hydrolysis reaction of glycolic acid: Add 15mL of concentrated sulfuric acid and 50mL of water into a flask equipped with a thermometer, mechanical stirring, dropping funnel, and reflux condenser, and add 100mL of hydroxyacetonitrile aqueous solution dropwise under stirring. Insulate at -60°C for 4 hours, cool to room temperature, and obtain an aqueous solution of glycolic acid and ammonium bisulfate;

[0027] (2) Neutralization reaction: Add concentrated ammonia water to carry out neutralization reaction under stirring until the pH of the reaction system is 7.5;

[0028] (3) Desalination: add 300mL of anhydrous isopropanol to the product of step (2), stir at room temperature for 0.5 hours, filter with suction, dry the filter cake obtained by suction filtration, recover the filtrate, add 5g of charcoal for injection to decolorize After obtaining a colorless transparent liquid;

[...

Embodiment 3

[0032] A method for preparing solid glycolic acid, comprising the following steps:

[0033] (1) Hydrolysis reaction of glycolic acid: Add 15mL of concentrated sulfuric acid and 50mL of water into a flask equipped with a thermometer, mechanical stirring, dropping funnel, and reflux condenser, and add 100mL of hydroxyacetonitrile aqueous solution dropwise under stirring, wherein, hydroxyacetonitrile aqueous solution The mass fraction is 50%, and after the addition, it is kept at 50-60°C for 4h, cooled to room temperature, and an aqueous solution of glycolic acid and ammonium bisulfate is obtained;

[0034] (2) Neutralization reaction: Add concentrated ammonia water to carry out neutralization reaction under stirring until the pH of the reaction system is 7;

[0035] (3) Desalination: add 300mL of anhydrous isopropanol to the product of step (2), stir at room temperature for 0.5 hours, filter with suction, and dry the filter cake obtained by suction filtration at 80°C After 6 ho...

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Abstract

A method for preparing solid glycolic acid comprises the following steps: (1) hydrolysis reaction of glycolic acid: taking concentrated sulfuric acid, water and a glycolonitrile water solution as raw materials for hydrolysis reaction of glycolic acid; (2) neutral reaction: adding concentrated ammonia water while stirring for neutral reaction; (3) desalting: adding anhydrous isopropyl alcohol into a product of the step (2), stirring, performing suction filtration, drying filter cake obtained through suction filtration, retrieving filtrate, and adding injection carbon for decoloration to obtain a colorless transparent liquid; (4) alcohol recovery; and (5) crystallization: performing cooling crystallization, stopping cooling when the temperature of feed liquid reaches 5-20 DEG C, preserving the temperature for 1 h at the temperature, performing suction filtration, washing filter cake with 100 mL distilled water to obtain a glycolic acid wet product, and conducting vacuum drying at 30 DEG C for 6 h to obtain solid glycolic acid. The method for preparing the solid glycolic acid is simple to operate and high in product yield and purity.

Description

technical field [0001] The invention belongs to the field of preparation of glycolic acid, in particular to a method for preparing solid glycolic acid. Background technique [0002] Glycolic acid, also known as glycolic acid, is the simplest aliphatic hydroxy acid. Since it has both a hydroxyl structure and a carboxyl structure, it can be regarded as an alcohol or a carboxylic acid. It is an important organic synthesis intermediate and chemical product, which has a wide range of applications. In nature, it mainly exists in sugar beets, sugar cane and immature grapes. The currently discovered application fields mainly include: chemical cleaning, biodegradable materials, fungicides, daily chemicals, electroplating surface treatment, etc. With the deepening of its research and the development of new uses, the demand for p-glycolic acid is increasing day by day. [0003] At present, the production methods of glycolic acid in China mainly include: 1. Chloroacetic acid alkalin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/08C07C51/42C07C59/06
CPCC07C51/08C07C51/42
Inventor 李长英
Owner SHAANXI YIPINDA PETROCHEM CO LTD
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