Technology of preparing hdyroxy acetic acid

A technology of glycolic acid and methyl glycolate, applied in nitrile preparation, organic chemistry, etc., can solve the problems of high raw material cost, low production efficiency, complex process, etc., and achieve mild and easy-to-control reaction conditions, simple production equipment, and wide sources Effect

Active Publication Date: 2006-01-25
XINMAO DACRON CHEM GENERAL PLANT TAICANG CITY
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  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Alkaline hydrolysis of chloroacetic acid produces glycolic acid and sodium chloride. This process requires concentration and esterification to remove most of the sodium chloride, and then ion membrane electrodialysis to remove residual sodium chloride. This process requires large investment and raw material costs. High and consumes a lot of electricity, and the final product still has chloride and sodium ions
[0004] Ethylene glycol reacts with air in the presence of a catalyst to form ethyl alde

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Add 80 milliliters of water and 210 grams of 98% sulfuric acid earlier in the 1000 milliliter flask equipped with stirring thermometer, dropping funnel and reflux distillation condenser, heat with oil bath, add dropwise 228 grams of 50% hydroxyacetonitrile aqueous solution under stirring, Keep the temperature at 120°C for hydrolysis reaction for 5 hours, distill off 100 grams of aqueous solution, then add methanol for esterification reaction under reflux conditions and distill out the mixture of reaction product methanol, water, and methyl glycolate, and esterify with methanol, which The esterification process is carried out in three times by normal pressure and reduced pressure distillation. The amount of methanol added is 250 grams, 130 grams and 80 grams respectively. The time of esterification reaction is 5 hours, 3 hours and 1 hour respectively. Put the evaporated mixture and 250 grams of distilled water in a 1000 ml flask equipped with a stirring thermometer, a rec...

Embodiment 2

[0040] In a 200-liter glass-lined reaction kettle with a stirrer, a thermometer, a reflux pipe, a distillation pipe and a drip feeding pipe, first add 16 kilograms of water and 40 kilograms of 98% sulfuric acid to heat with steam, and gradually add 50% of hydroxyacetonitrile. The aqueous solution was 45.6 kg, the reaction temperature was maintained at 115-120°C, the hydrolysis reaction was carried out for 6 hours, and 19.5 kg of the aqueous solution was distilled off under reduced pressure. According to the conditions of Example 1, methanol was added three times for esterification, and the reaction product was distilled off under normal pressure and reduced pressure. The amount of methanol added three times was 48 kg, 25 kg, and 25 kg respectively. Collect the distilled aqueous solution and the distilled mixture after esterification and 50 kg of distilled water in the same reaction kettle as in this example, heat and stir with steam for 4 hours for hydrolysis, keep the temperat...

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PUM

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Abstract

The invention provides a process for preparing hydroxy-acetic acid which comprises, hydrolyzing hydroxyl acetonitrile aqueous solution and sulfuric acid to obtain hydroxy-acetic acid and the aqueous solution of the acidic salts of ammonium sulfate, then charging methanol into the aqueous solution for esterification, and distilling the mixture of methanol, water and hydroxy-acetic acid methyl ester, remaining the acidic salts of ammonium sulfate, then charging water into the distilled mixture for the hydrolysis of hydroxy-acetic acid methyl ester, separating methanol and obtaining crystallized hydroxy-acetic acid.

Description

technical field [0001] The invention relates to a process for preparing glycolic acid. Background technique [0002] The preparation method of the glycolic acid mentioned in the known literature has: the chloroacetic acid alkali hydrolysis of Japanese Patent Application No. 9-21684, concentration, after removing alkali metal chlorides, carry out electrodialysis with water dilution again; Kaiping 11-335319 mentions the use of ethylene glycol and nitrogen in the air to react in the gas phase with metal silver as a catalyst, and then through rectification and hydrolysis; U.S. Patent US4054601 and Chinese Patent Publication No. are the disclosed acidic hydrolysis of hydroxyacetonitrile CN1066650A After diluting with water, it can be extracted with butyl phosphate, trialkylphosphine hydroxide, etc. and prepared by back-extraction with water. [0003] Alkaline hydrolysis of chloroacetic acid produces glycolic acid and sodium chloride. This process requir...

Claims

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Application Information

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IPC IPC(8): C07C59/06C07C51/08
Inventor 陈延全张建忠秦伟星
Owner XINMAO DACRON CHEM GENERAL PLANT TAICANG CITY
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