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Esterification conversion method of gulonic acid

A technology of gulon ester and gulon acid, which is applied in the field of biomedicine, can solve the problems of being unable to apply large-scale production, affecting the extinction of VC finished products, and not yet expanding production, so as to achieve the effects of increasing molar conversion rate, low cost and shortening reaction time

Pending Publication Date: 2020-02-04
NINGXIA QIYUAN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the above-mentioned alkali conversion method has simple process and mild reaction conditions, the conversion rate is relatively low.
Many scholars have made improvements and optimizations on this basis. For example, postgraduate students of Tianjin University use dry hydrogen resin as a catalyst to react in the liquid phase in a self-developed fixed-bed catalytic reactor to obtain methyl guronate, which is then reacted with sodium bicarbonate to generate VC. Sodium, its molar conversion rate has increased by 2.99%, but this process still cannot be applied to large-scale production at present; People such as Du Minghui used sodium carbonate instead of sodium bicarbonate to carry out lactonization reaction in 2011, and the conversion rate was increased to 96.01%, but The yellow color of the obtained material will affect the extinction of VC finished products; some scholars have designed an online dehydration device and a continuous production device starting from the device, but they have not yet expanded production.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] (1) Weigh suspension: to 20m 3 Add 9m into the reactor with interlayer 3 For industrial methanol, start stirring, slowly add 45 L of concentrated sulfuric acid, continue stirring, add 2000Kg (purified) dried guaronic acid (moisture content 0.3%).

[0020] (2) Methyl esterification reaction: slowly raise the temperature of the system to 40°C, then stir for 3 hours, then continue to raise the temperature to 63°C, and react for 1 hour. Finally, the temperature was lowered to 40°C, and the methyl esterification reaction was completed, and the esterification rate was 97.8%.

[0021] (3) Conversion (lactonization) reaction: When the temperature of the system drops to 40°C, slowly add 1050Kg of sodium bicarbonate while stirring, stir for 30 minutes, then add 88L of deionized water to the reaction system, and raise the temperature to 55°C. Fully react for 6h.

[0022] (4) Cooling and centrifugation: Pour the feed liquid into the crystallization tank, stir and cool down to 2°...

Embodiment 2

[0024] (1) Weigh suspension: to 20m 3 Add 10.5m into the reactor with interlayer 3 For industrial methanol, start stirring, slowly add 45L of concentrated sulfuric acid, continue stirring and add 3000Kg (purified) dried guaronic acid (moisture 0.2%).

[0025] (2) Methyl esterification reaction: slowly raise the temperature of the system to 50°C and then stir for 2.0 hours, then continue to raise the temperature to 65°C for 0.7 hours. Finally, the temperature was lowered to 45°C, the methyl esterification reaction was completed, and the esterification rate was 98.8%.

[0026] (3) Conversion (lactonization) reaction: When the temperature of the system drops to 45°C, slowly add 1470Kg of sodium bicarbonate while stirring, stir for 30 minutes, then add 330L of deionized water to the reaction system, and raise the temperature to 60°C. Fully react for 4h.

[0027] (4) Cooling and centrifugation: Pour the feed liquid into the crystallization tank, stir and cool down to 0°C, and ce...

Embodiment 3

[0029] (1) Weigh suspension: to 20m 3 Add 10m into the reactor with interlayer 3 For industrial methanol, start stirring, slowly add 60 L of concentrated sulfuric acid, continue stirring and add 1500Kg (purified) dried guaronic acid (moisture 0.4%).

[0030] (2) Methyl esterification reaction: slowly raise the temperature of the system to 60°C, then stir for 1.0h, then continue to raise the temperature to 65°C, and react for 0.5h. Finally, the temperature was lowered to 50° C., and the methyl esterification reaction ended. The esterification rate is 99.3%.

[0031] (3) Conversion (lactonization) reaction: When the temperature of the system drops to 50°C, slowly add 900Kg of sodium bicarbonate while stirring, stir for 30 minutes, then add 480L of deionized water to the reaction system, and raise the temperature to 65°C. Fully react for 3h.

[0032] (4) Cooling and centrifugation: Pour the feed liquid into the crystallization tank, stir and cool down to 0°C, and centrifuge t...

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Abstract

The invention relates to an esterification conversion method of gulonic acid. The method comprises: uniformly mixing industrial methanol and concentrated sulfuric acid, adding a gulonic acid dry product in a stirring state, carrying out a methyl esterification reaction in a staged temperature changing manner, sequentially adding sodium bicarbonate and deionized water, heating, carrying out a conversion reaction, cooling after the reaction is finished, and carrying out centrifugal separation to obtain the sodium ascorbate. According to the invention, the gulonic acid esterification conversion method is simple in process, easy to operate, low in cost, capable of greatly increasing the molar conversion rate from gulonic acid to VC sodium (increased by 1.5-3.2% compared with the prior art) andsuitable for large-scale production.

Description

technical field [0001] The invention belongs to the technical field of biomedicine, and in particular relates to a gulong esterification transformation method. Background technique [0002] Vitamin C (VC), also known as L-ascorbic acid, has a strong antioxidant effect due to its allenol structure, and is widely used in the fields of medicine and health care, food additives, cosmetics and feed additives. [0003] Gulonic acid is converted into one of the indispensable links in the production process of VC. At present, there are mainly two methods: acid conversion and alkali conversion. Among them, the alkali conversion method was successfully developed by Northeast Pharmaceutical General Factory in 1979. It is the current domestic technology. Gulonic acid and methanol are esterified under the catalysis of concentrated sulfuric acid to generate guronic acid methyl ester, which undergoes lactonization reaction under the action of sodium bicarbonate to convert VC sodium salt, an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D307/62
CPCC07D307/62
Inventor 李学兵慕金凤张志
Owner NINGXIA QIYUAN PHARMA
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