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Preparation method for 4-hydroxy-3-methoxy benzoic acid

A technology of methoxybenzoic acid and hydroxyl, applied in the field of preparation of 4-hydroxy-3-methoxybenzoic acid, can solve the problems of harsh reaction conditions, high production cost, low safety, etc. The effect of low production cost and high safety

Active Publication Date: 2015-09-23
安徽华馨生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Aiming at the defects existing in the above-mentioned prior art, the technical problem to be solved by this invention is to provide a kind of preparation method of 4-hydroxyl-3-methoxybenzoic acid, described this 4-hydroxyl-3-methoxy The preparation method of benzoic acid should solve technical problems such as harsh reaction conditions, high production cost, many steps, large pollution and low safety in the prior art

Method used

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  • Preparation method for 4-hydroxy-3-methoxy benzoic acid
  • Preparation method for 4-hydroxy-3-methoxy benzoic acid
  • Preparation method for 4-hydroxy-3-methoxy benzoic acid

Examples

Experimental program
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Effect test

Embodiment l

[0024] The 500ml three-necked flask is equipped with a magnetic stirrer, a thermometer, and a detachable reflux condensing device. Add 24.8g (0.2mol) guaiacol, then add 23.2g 50% glyoxal (0.2mol) (that is, the molar ratio of guaiacol to glyoxal is 1:1), add 10% hydroxide Sodium adjusts the pH value to 12.0-12.5, stirs, and reacts at 35-40° C. for 6.0 hours. After the reaction is completed, dilute hydrochloric acid is used to adjust the pH value of the reaction solution to 2-3. After the product is extracted 3 times with ethyl acetate, it is concentrated under reduced pressure to obtain the crude product. The HPLC analysis content of the product vanillic acid is 25%, and the crude product is recovered under reduced pressure. Guaiacol, the raw material for the reaction, and the residue were recrystallized with water to obtain 6.3 g of a white solid, with a reaction selectivity of 83% and a yield of 75%.

[0025] m.p.206~207℃(lit.m.p.208~210℃); 1H NMR (500MHz, DMSO-d6)d 12.73(br...

Embodiment 2

[0027] The 500ml three-necked flask is equipped with a magnetic stirrer, a thermometer, and a detachable reflux condensing device. Add 12.4g (0.1mol) guaiacol, then add 23.2g 50% glyoxal (that is, the molar ratio of guaiacol to glyoxal is 1:2), add 10% potassium hydroxide solid to adjust the pH value 11.5-12.0, stirred, 30 ~ 35 ℃ heat preservation reaction for 6.0 hours. After the reaction is completed, dilute sulfuric acid is adjusted to adjust the pH of the reaction solution to 2-3. After the product is extracted 3 times with ethyl acetate, it is concentrated under reduced pressure to obtain the crude product. The product vanillic acid HPLC content is 18%, and the crude product is recovered under reduced pressure. The raw material was guaiacol, and the residue was crystallized with water to obtain 2.3 g of white powdery crystals, with a reaction selectivity of 81% and a yield of 70%.

Embodiment 3

[0029] The 500ml three-necked flask is equipped with a magnetic stirrer, a thermometer, and a detachable reflux condensing device. Add 12.4g (0.1mol) guaiacol, then add 46.4g 50% glyoxal (that is, the molar ratio of guaiacol to glyoxal is 1:4), add 30% sodium hydroxide to adjust the pH value 13.0-13.5, stirred, and kept at 45-50°C for 2-2.5 hours. After the reaction is completed, adjust with dilute hydrochloric acid to adjust the pH value of the reaction solution to 2-3. After the product is extracted 3 times with ethyl acetate, it is concentrated under reduced pressure to obtain the crude product. The HPLC content of the product vanillic acid is 16%. The raw material guaiacol, the residue was recrystallized with water to obtain 1.69g of white solid, the reaction selectivity was 73%, and the yield was 58%.

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Abstract

The invention discloses a preparation method for 4-hydroxy-3-methoxy benzoic acid. The preparation method comprises the following stesp: using guaiacol as a starting material and water as a solvent, and through the action of a carboxylation reagent under the alkaline condition, synthesizing 4-hydroxy-3-methoxy benzoate only by one-step reaction; acidifying after the reaction, extracting and concentrating under reduced pressure to obtain a crude product; after the raw material of guaiacol is recycled, recrystallizing with water to obtain a pure product, namely 4-hydroxy-3-methoxy benzoic acid. According to the preparation method, the raw material is cheap and easy to obtain, the reaction condition is mild, the operation is simple and convenient, the production cost is relatively low, and the preparation method has a relatively wide industrial application prospect.

Description

technical field [0001] The invention belongs to the field of chemical industry, in particular to a kind of 4-hydroxyl-3-methoxybenzoic acid, specifically a kind of preparation method of 4-hydroxyl-3-methoxybenzoic acid. Background technique [0002] 4-Hydroxy-3-methoxybenzoic acid, also known as vanillic acid, or vanillic acid, is a widely used organic compound, which can be widely used in the field of medicine as an antioxidant or tyrosinase inhibitor. Its anti-oxidation properties are used in the food field as a food additive. In addition, it has been widely used in the agricultural field, so it has a good application prospect. [0003] The synthetic preparation of 4-hydroxy-3-methoxybenzoic acid has been extensively studied. The traditional chemical method is to use vanillin as raw material through oxidation (silver oxide) or alkali fusion (potassium hydroxide, temperature below 240°C). This method has the disadvantages of expensive raw materials, harsh reaction conditio...

Claims

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Application Information

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IPC IPC(8): C07C51/00C07C65/21C07C51/42
CPCC07C51/00C07C51/42C07C65/21
Inventor 毛海舫霍浩华王朝阳赵飞飞姚跃良孙揭阳王立志
Owner 安徽华馨生物科技有限公司
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