Method for preparing 3-methoxy-4-hydroxy mandelic acid

A technology of hydroxymandelic acid and methoxyl group, applied in the field of preparing 3-methoxy-4-hydroxymandelic acid by glyoxylic acid method, can solve problems such as unsatisfactory yield, and achieve improved utilization rate and condensation product yield improved effect

Active Publication Date: 2011-06-08
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Over the years, experts and scholars in some universities, enterprises and institutions have taken improving the yield of vanillin and ethyl vanillin as an important subject to study, but the yield is still not ideal.

Method used

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  • Method for preparing 3-methoxy-4-hydroxy mandelic acid
  • Method for preparing 3-methoxy-4-hydroxy mandelic acid
  • Method for preparing 3-methoxy-4-hydroxy mandelic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0027] (1) Weigh 22.3g of glyoxylic acid with a content of 33.3wt%, add it into 48.5g of water under stirring to make 10.56wt% glyoxylic acid, and slowly add 30wt% sodium hydroxide solution dropwise at a temperature of 10°C , adjust the pH value of the solution to 4.5, and prepare the sodium glyoxylate solution for use.

[0028] (2) Weigh 16.0g of guaiacol with a content of 99wt%, add 180g of water under nitrogen protection and stirring, the reaction temperature is 10°C, slowly add 30wt% sodium hydroxide solution dropwise, and adjust the pH value of the solution to 11 , to prepare sodium guaiacol solution.

[0029] (3) Control the reaction temperature by a water bath at 10-13°C, slowly add the sodium glyoxylate solution prepared in the above (1) dropwise to the sodium guaiacol solution prepared in the above (2) under nitrogen protection and stirring In, add dropwise for 52min. Stirring was continued for 1 h, and the reaction temperature was static for 27 h. Then use 50wt% s...

Embodiment 2

[0031] (1) Take by weighing 22.3g content and be the glyoxylic acid of 33.3wt%, add under stirring in 48g water, be made into the glyoxylic acid of 10.56wt%, under 20 ℃ of reaction temperature, slowly add dropwise the sodium hydroxide solution of 30wt%, Adjust the pH value of the solution to 4.5 and set it aside.

[0032] (2) Take 20.1g of guaiacol with a content of 99wt%, add 180g of water under nitrogen protection and stirring, at a reaction temperature of 12°C, slowly add 30% sodium hydroxide solution dropwise, and adjust the pH value of the solution to 11, stand-by.

[0033] (3) Control the reaction temperature by a water bath at 10-13°C, under nitrogen protection and stirring, slowly add the sodium glyoxylate solution prepared in the above (1) dropwise to the sodium guaiacol prepared in the above (2) In the solution, after adding dropwise for 60 minutes, continue to stir for 1 hour, then react statically at the above reaction temperature for 27 hours, and then use 50 wt%...

Embodiment 3

[0035] (1) Take by weighing 22.3g content and be the glyoxylic acid of 33.3wt%, add under stirring in 48g water, be made into the glyoxylic acid of 10.56wt%, under the reaction temperature 25 ℃, slowly drop the sodium hydroxide solution of 30wt%, Adjust the pH value of the solution to 4.5 and set it aside.

[0036] (2) Take 20.1g of guaiacol with a content of 99wt%, add 180g of water under nitrogen protection and stirring, at a reaction temperature of 15°C, slowly add 30wt% sodium hydroxide solution dropwise, and adjust the pH value of the solution to 11, stand-by.

[0037] (3) Control the reaction temperature by a water bath at 12-15°C, under nitrogen protection and stirring, slowly add the sodium glyoxylate solution prepared in the above (1) dropwise to the sodium guaiacol prepared in the above (2) Add dropwise to the solution for 65 minutes, continue to stir for 1 hour, and react statically at the above temperature for 26 hours, then acidify the reaction solution with 50 w...

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Abstract

A method for preparing 3-methoxy-4-hydroxy mandelic acid adopts guaiacol and glyoxylic acid as raw materials, and comprises the following steps: slowly adding a 30 wt% sodium hydroxide solution into the glyoxylic acid solution with stirring, allowing the mixed solution to react at a reaction temperature of 0-50 DEG C and a pH value of 1-7 to obtain a sodium glyoxylate solution; adding the guaiacol into water with stirring and under the protection of nitrogen gas, slowly adding the 30 wt% sodium hydroxide solution, allowing the mixed solution to react at a reaction temperature of 0-50 DEG C and a pH value of 11-12 to obtain guaiacol sodium; slowly and dropwisely adding the sodium glyoxylate solution into the guaiacol sodium solution with stirring and under the protection of nitrogen gas, with the mole ratio of the sodium glyoxylate and the guaiacol sodium being 1:1.2-2, allowing the mixed solution to react at a reaction temperature of 0-20 DEG C and a pH value of 11-12, 30-90 min afterthe dropwise addition, stirring the mixed solution for 1-3 hours, stopping the reaction at the reaction temperature for 24-36 hours, then acidifying the reaction solution by a 50 wt% sulfuric acid solution to control the pH value to be 4-5. The yield of the reaction is above 95 wt%.

Description

technical field [0001] The invention relates to a method for preparing vanillin intermediate 3-methoxy-4-hydroxymandelic acid, in particular to a method for preparing 3-methoxy-4-hydroxymandelic acid by glyoxylic acid method. Background technique [0002] 3-methoxy-4-hydroxymandelic acid is an important intermediate in the synthesis of vanillin. Vanillin or ethyl vanillin is a broad-spectrum spice, which can be used as a fixative, flavoring agent and odor changing agent; in addition, it is also an important intermediate for synthetic medicine. [0003] At present, in the process of preparing 3-methoxy-4-hydroxymandelic acid by glyoxylic acid method, there is no systematic investigation on the stability of the raw materials after they are formulated into solutions, and the condensation reaction is carried out at a relatively high temperature, resulting in increased side reactions. The guaiacol selectivity and product yield are low, and the product has dark color and a lot of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C59/64C07C51/367
Inventor 张新胜李江利陈文博李正张正春王淑娟刘宇石大川魏国峰陈志明项文言姜悦
Owner PETROCHINA CO LTD
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