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Preparation method of hydroxyacetic acid

A technology of glycolic acid and methyl glycolate, applied in the field of preparation of glycolic acid, can solve the problems of high manufacturing cost, complicated operation and high working hours, and achieve the effects of reducing production cost, shortening reaction time and improving competitiveness.

Active Publication Date: 2015-07-01
太仓市新毛涤纶化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The former causes the distilled methanol to be recycled after rectification, and the rectification consumes a lot of energy. The latter causes variable process parameters in the operation process, cumbersome operation, low efficacy, high energy consumption, and high working hours, resulting in high manufacturing cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Add 40 milliliters of water and 100 grams of concentrated sulfuric acid with a mass concentration of 98% into a 1000 milliliter flask to form a 70% sulfuric acid solution, add 114 grams of hydroxyacetonitrile aqueous solution with a mass concentration of 50% under heating and stirring, keep the temperature at 130 ° C, and hydrolyze 4 hours, and steamed 50 milliliters of water, then added 60 g of mass concentration of 85% aqueous methanol, reacted at 110 ° C, after 30 minutes at this temperature, continuously added 200 grams of methanol aqueous solution of 85% within 3 hours, While continuously adding methanol aqueous solution, the mixture of methanol, water and methyl glycolate was continuously distilled off, and the residue was the acid salt of ammonium sulfate.

[0032] Collect the evaporated mixture, add 150 ml of deionized water to the ester hydrolysis kettle, carry out ester hydrolysis at 100°C under stirring, distill methanol, and then distill part of the water...

Embodiment 3

[0037] Add 80 milliliters of pure water and 210 grams of concentrated sulfuric acid with a mass concentration of 98% in the reaction kettle, add 228 grams of hydroxyacetonitrile aqueous solution with a mass concentration of 50% under stirring, and carry out a hydrolysis reaction at 120 ° C for 5 hours, while steaming about 100 grams of water. Then, 135 grams of aqueous methanol solutions with a mass concentration of 85% were dropped into the reactor, heated to 110° C., and after esterification for 2 hours, 400 grams of aqueous methanol solutions with a mass concentration of 85% were continuously added at this temperature within 5 hours. While adding methanol aqueous solution, the mixture of methanol, water and methyl glycolate was distilled off continuously, and the residue was the acid salt of ammonium sulfate.

[0038] Put the distilled mixture in an ester hydrolysis bottle, add 200 ml of water distilled during the acid hydrolysis of hydroxyacetonitrile aqueous solution,...

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Abstract

The invention relates to a preparation method of hydroxyacetic acid. The preparation method comprises the following steps: performing a hydrolysis reaction on an aqueous solution of hydroxynitrile and a sulfuric acid solution having the mass concentration of 70%-90% at a temperature within the range of 120-140 DEG C, thereby obtaining the mixed solution of hydroxyacetic acid and an acidic salt ammonia sulfate; at the same time of performing an esterification reaction by adding methanol to the mixed solution, distilling out the mixture of methanol, water and methyl hydroxylacetate, and controlling the temperature of the whole process within the range of 110-120 DEG C; adding water to adjust the mass percentage of methyl hydroxylacetate in the mixture to the range of 10%-25%, hydrolyzing methyl hydroxylacetate at a temperature less than or equal to 100 DEG C into hydroxyacetic acid, separating out methanol and water, and recycling separated methanol. According to the preparation method, due to the improvement of the reaction temperatures, the raw material concentration and the preparation method, the reaction time is shortened and the energy consumption and the methanol loss are reduced under the premise of guaranteeing the yield; as a result, the production cost is greatly reduced and the product competitiveness is improved.

Description

technical field [0001] The invention relates to a preparation method of glycolic acid. Background technique [0002] Glycolic acid has hydroxyl and carboxyl groups and is a very important organic compound. Various preparation methods are provided in known literature introductions and patents issued by the United States, Europe and Japan. The process for preparing glycolic acid proposed by disclosed CN100343220C Chen Yanquan, Zhang Jianzhong, and Qin Weixing is to hydrolyze the aqueous solution of hydroxyacetonitrile with sulfuric acid, and to separate the glycolic acid from the mixture of hydrolyzed product glycolic acid and ammonium sulfate acid salt, using methanol Esterification with glycolic acid and using ammonium sulfate acid salt as a catalyst, and then rehydrolyze the distilled methyl glycolate to obtain a water bath of pure glycolic acid, then decondense and crystallize, and dry to obtain crystal glycolic acid. [0003] However, in the disclosed technique, the hyd...

Claims

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Application Information

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IPC IPC(8): C07C59/06C07C51/09
CPCC07C51/08C07C51/493C07C59/06
Inventor 张建忠
Owner 太仓市新毛涤纶化工有限公司
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