Preparation method of 3-ethoxy-4-hydroxymandelic acid used as intermediate for synthesizing ethyl vanillin

A technology of hydroxymandelic acid and ethyl vanillin, which is applied in the field of preparation of ethyl vanillin synthesis intermediate 3-ethoxy-4-hydroxymandelic acid, which can solve the problems of low product yield and long reaction time problem, achieve the effect of improving reaction selectivity, shortening reaction time and speeding up reaction speed

Inactive Publication Date: 2011-09-21
CHONGQING THRIVE CHEM
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Problems solved by technology

[0003] At present, the glyoxylic acid method is mainly used to synthesize 3-ethoxy-4-hydroxymandelic acid (the chemical reaction formula is as follows), which has the advantages of simple process route and easy operation, but the existing method has long reaction time and low product yield Not enough

Method used

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  • Preparation method of 3-ethoxy-4-hydroxymandelic acid used as intermediate for synthesizing ethyl vanillin
  • Preparation method of 3-ethoxy-4-hydroxymandelic acid used as intermediate for synthesizing ethyl vanillin
  • Preparation method of 3-ethoxy-4-hydroxymandelic acid used as intermediate for synthesizing ethyl vanillin

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Embodiment 1～7

[0014] The synthesis of embodiment 1~7,3-ethoxy-4-hydroxymandelic acid

[0015] Method: includes the following steps:

[0016] a. Weigh 50.0g of glyoxylic acid with a mass percentage of 40%, add 83.6g of water, stir evenly at room temperature, then add dropwise 65mL of a 14.5% sodium hydroxide aqueous solution under stirring conditions, and adjust the pH to 5.0 ~5.5 to obtain glyoxylic acid solution;

[0017] b. Add 42.3g of 2-ethoxyphenol and 163.9mL of water into the three-necked flask, stir evenly, heat to 30°C, add dropwise 50mL of aqueous sodium hydroxide solution with a mass fraction of 8.3% under stirring conditions, and adjust the pH to 10-12, after 0.5 hours, the 2-ethoxyphenol alkaline solution was obtained;

[0018] c. At a temperature of 30°C, add 90 mL of the glyoxylic acid solution obtained in step a and an aqueous sodium hydroxide solution with a mass fraction of 8.3% dropwise to the 2-ethoxyphenol alkaline solution obtained in step b, respectively, for 1 hour...

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Abstract

The invention discloses a preparation method of 3-ethoxy-4-hydroxymandelic acid, which is an intermediate used in the synthesis of ethyl vanillin. The preparation method comprises the following steps: adding water into glyoxalic acid, well-mixing the mixture, and using a sodium hydroxide solution to regulate the pH value of the mixture to 5.0 to 5.5, such that a glyoxalic acid solution is obtained; adding water into 2-ethoxyphenol, well-mixing the mixture, and using the sodium hydroxide solution to regulate the pH value of the mixture to 10 to 12 under a temperature of 25 to 30 DEG C, such that a 2-ethoxyphenol solution is obtained; simultaneously dropping the glyoxalic acid solution and the sodium hydroxide solution into the 2-ethoxyphenol solution under a temperature of 25 to 30 DEG C, than heating the mixture to a temperature of 50 to 60 DEG C, stirring for 1 to 3 hours with the temperature maintained, such that 3-ethoxy-4-hydroxymandelic acid is obtained. According to the invention, through an optimized arrangement of reaction temperatures, the reaction time is substantially reduced, and the production yield is substantially increased.

Description

technical field [0001] The invention relates to a preparation method of compounds, in particular to a preparation method of ethyl vanillin synthesis intermediate 3-ethoxy-4-hydroxymandelic acid. Background technique [0002] 3-ethoxy-4-hydroxymandelic acid is an important intermediate in the synthesis of ethyl vanillin (chemical name 3-ethoxy-4-hydroxybenzaldehyde). Ethyl vanillin is a broad-spectrum flavor with a wide range of uses, such as flavoring raw materials, flavoring agents or fixatives in the food, daily chemical, and tobacco industries, including beverages, candies, cakes, biscuits, bread, and roasted seeds and nuts, etc. Most of the food consumption. [0003] At present, the glyoxylic acid method is mainly used to synthesize 3-ethoxy-4-hydroxymandelic acid (the chemical reaction formula is as follows), which has the advantages of simple process route and easy operation, but the existing method has long reaction time and low product yield Waiting is not enough. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C59/64C07C51/367
Inventor 肖琳珊洪炜马学兵赵华文韦勇谭修万陈杰
Owner CHONGQING THRIVE CHEM
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