Synthesis method of high-purity high-yield syringic acid

A synthesis method and a high-yield technology, applied in the field of high-purity and high-yield syringic acid synthesis, can solve problems such as poor appearance quality, low product purity, immature cost and technology, and achieve reduced synthesis cost and high purity. , easy manipulation and industrialized effects

Inactive Publication Date: 2015-06-10
SHOUGGUANG HAOYUAN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The mainstream method for preparing syringic acid in China is to use 3,4,5-trimethoxybenzoic acid to selectively demethylate and synthesize syringic acid. There are many, but most of the content is concentrated on the acid-base catalyst to improve the yield of demethylation, and there is no substantial improvement on some inherent disadvantages of the reaction itself, such as low product purity and poor appearance quality.
In the past few years, due to problems such as cost and immature technology, there were basically no reports on the preparation of syringic acid from syringaldehyde (3,5-dimethoxy-4-hydroxybenzaldehyde)

Method used

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  • Synthesis method of high-purity high-yield syringic acid
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  • Synthesis method of high-purity high-yield syringic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] A kind of synthetic method of high purity, high yield syringic acid, comprises the following steps:

[0032] (1) Esterification:

[0033] Put 18.2g (0.1mol) of syringaldehyde (3,5-dimethoxy-4-hydroxybenzaldehyde) and 25.5g (0.25mol) of acetic anhydride in a 50ml reaction flask, stir and heat up to reflux for 2 hours, then cool down to 35°C;

[0034] (2) Oxidation:

[0035] Continuously and evenly drop 24.2g (0.2mol) of 28% hydrogen peroxide into the esterification reaction solution in step (1) within 0.5 hours, then raise the temperature to 55°C, keep it warm for 10 hours, cool down to 5°C, filter with suction, wash with water Cake to pH=7;

[0036] (3) Hydrolysis:

[0037] Put the filter cake into a 100ml reaction bottle, add 48g of 10% sodium hydroxide aqueous solution, heat up to 80°C, keep stirring for 3 hours, add 98% concentrated sulfuric acid dropwise to pH = 2, cool the system to 25°C, and filter with suction , wash the filter cake with water to pH=7, and t...

Embodiment 2

[0040] (1) Esterification:

[0041] Put 728g (4.0mol) of syringaldehyde, 1020g (10.0mol) of acetic anhydride, and 800g of acetic acid into a 2000ml reaction flask, stir and heat up to reflux for 3 hours, then cool down to 30°C;

[0042] (2) Oxidation:

[0043] Continuously and evenly drop 680g (5.6mol) of 28% hydrogen peroxide into the esterification reaction solution in step (1) within 2 hours, then raise the temperature to 60°C, keep it warm for 14 hours, cool down to 3°C, filter with suction, and wash the filter cake with water to pH=7;

[0044] (3) Hydrolysis:

[0045] Put the filter cake into a 3000ml reaction bottle, add 2080g of 10% sodium hydroxide aqueous solution, heat up to 110°C, keep stirring for 1.5 hours, then add 98% concentrated sulfuric acid dropwise to pH = 2, cool the system to 20°C, and filter with suction , wash the filter cake with water to pH = 7, and the resulting off-white product is syringic acid.

[0046] The prepared syringic acid has a good ap...

Embodiment 3

[0048] According to the step of embodiment 1, change each process parameter, test:

[0049] Table 1 Raw material ratio

[0050]

[0051] Table 2 The process parameters of the present invention's synthetic syringic acid

[0052]

[0053] Table 3 The product index prepared by the present invention

[0054]

[0055] Tested:

[0056] The acid anhydride is acetic anhydride, phthalic anhydride, preferably acetic anhydride.

[0057] Described solvent is acetic acid, acetone, toluene, dichloroethane, preferably acetic acid.

[0058] Described mineral acid is hydrochloric acid, sulfuric acid, preferably sulfuric acid.

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Abstract

The invention discloses a synthesis method of high-purity high-yield syringic acid. The method is characterized by comprising the following steps: esterification, oxidation and hydrolysis, wherein in the esterification step, the molar ratio of syringaldehyde, acid anhydride and solvent is 1:1.5-4:0-10; heating and reflowing are performed for 2-3 hours and cooling is performed for 30-70 DEG C in the esterification step; in the oxidation step, the molar ratio of the syringaldehyde and hydrogen peroxide is 1:1.5-3.5; in the oxidation step, the hydrogen peroxide is continuously added into esterification reaction solution in 0.5-2 hours. The yield of a product prepared by the method is greater than 86.5 percent, and the purity of the product is greater than 98.6 percent.

Description

technical field [0001] The invention relates to a method for synthesizing syringic acid with high purity and high yield, belonging to the technical field of organic chemical synthesis. Background technique [0002] Syringic acid (4-hydroxy-3,5-dimethoxybenzoic acid), an important pharmaceutical intermediate, is widely used in medicine, spices, pesticide chemistry and organic synthesis industries. Modern research has proved that syringic acid It has antibacterial and fungal effects, as well as sedative and local anesthetic effects, and has a certain international market. [0003] The mainstream method for preparing syringic acid in China is to synthesize syringic acid by selective demethylation of 3,4,5-trimethoxybenzoic acid. There are many documents in this regard, but most of the content focuses on improving the demethylation yield. On the high-efficiency acid-base catalyst, some inherent disadvantages of the reaction itself, such as low product purity and poor appearance...

Claims

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Application Information

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IPC IPC(8): C07C65/21C07C51/367
CPCC07C51/367C07C67/08C07C67/29C07C67/293C07C65/21C07C69/18
Inventor 黄都都于震
Owner SHOUGGUANG HAOYUAN CHEM
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