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Preparation method of pyrogallic acid

A technology of pyrogallic acid and gallic acid, which is applied in the field of preparation of pyrogallic acid, can solve the problems of increased difficulty in separation and purification, complicated operation and the like, and achieves the effect of avoiding decolorization and solvent separation treatment.

Pending Publication Date: 2021-10-29
遵义市倍缘化工有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in this process, the operation of the reaction is too complicated, and the catalyst added therein increases the difficulty of subsequent separation and purification.

Method used

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  • Preparation method of pyrogallic acid
  • Preparation method of pyrogallic acid
  • Preparation method of pyrogallic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Example 1, a method for pyrogallic acid, mixing gallic acid and deionized water at a mass ratio of 1:1, adding to the reaction kettle, sealing the reaction kettle, adjusting the temperature to 140°C, making it reaction, the pressure of the reaction kettle is 0.5~0.7MPa at this moment, react 10h, obtain the crude product of pyrogallic acid, and its conversion rate is 96%, after the reaction is completed, release the pressure of the reaction kettle for 1~2h, then carry out the crude product of pyrogallic acid After evaporating and concentrating to remove water for 5-6 hours, it is transferred to a sublimation device, and sublimated under reduced pressure to obtain a pyrogallic acid product with a purity of more than 99.7%.

Embodiment 2

[0020] Example 2, a method for pyrogallic acid, mixing gallic acid and deionized water at a mass ratio of 1:2, adding to the reaction kettle, sealing the reaction kettle, adjusting the temperature to 140°C, making it reaction, the pressure of the reaction kettle is 0.5~0.7MPa at this moment, react 10h, obtain the crude product of pyrogallic acid, and its conversion rate is 96%, after the reaction is completed, release the pressure of the reaction kettle for 1~2h, then carry out the crude product of pyrogallic acid Evaporate and concentrate to remove water for 6-8 hours, then transfer to a sublimation device, and sublimate under reduced pressure to obtain a pyrogallic acid product with a purity of more than 99.7%.

Embodiment 3

[0021] Example 3, a method for pyrogallic acid, mixing gallic acid and deionized water at a mass ratio of 1:1, adding to the reaction kettle, sealing the reaction kettle, adjusting the temperature to 160°C, making it reaction, the pressure of the reaction kettle is 1.0~1.7MPa at this moment, react for 6~8h, obtain pyrogallic acid crude product, its conversion rate is 98%, after the reaction is completed, let the reaction kettle depressurize for 1~2h, then pyrogallic acid The crude product is evaporated and concentrated to remove water for 5-6 hours, and then transferred to a sublimation device for sublimation under reduced pressure to obtain pyrogallic acid product with a purity of over 99.7%.

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Abstract

The invention discloses a preparation method of pyrogallic acid in the technical field of pyrogallic acid preparation, which comprises the following steps: adding gallic acid and water into a reaction kettle according to a mass ratio of 1: (0.5-5), sealing the reaction kettle for decarboxylation reaction for 0.5-10 hours under the conditions that the temperature is 140-220 DEG C and the pressure is 0.4-3.0 MPa to obtain pyrogallic acid, releasing the pressure after the decarboxylation reaction is finished, heating to evaporate water for a period of time, then transferring the material in the reaction kettle to a sublimation device and performing negative-pressure sublimation for purification. According to the pyrogallic acid prepared through the method, the conversion rate is 96% or above, the highest conversion rate can reach 100%, and the purity (HPLC) of the pyrogallic acid can reach 99.7% or above.

Description

technical field [0001] The invention relates to the technical field of pyrogallic acid preparation, in particular to a preparation method of pyrogallic acid. Background technique [0002] Gallic acid, also known as gallic acid, chemically named 3,4,5-trihydroxybenzoic acid, is an important organic raw material. It is used as an antioxidant and drug synthesis in chemical, pharmaceutical, food and electronic chemicals industries. Raw materials and the initial raw materials of photoresists have a wide range of uses, and their demand is increasing year by year. Pyrogallic acid is a product obtained by decarboxylation of gallic acid. It is also known as pyrogallol and pyrogallol, and its chemical name is 1,2,3-trihydroxybenzene. It is widely used in chemical analysis and photographic development. , fuel, paint, food, pharmaceutical, electronic materials, pesticides, national defense and other industries, and is also an important chemical raw material. In the prior art, the meth...

Claims

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Application Information

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IPC IPC(8): C07C37/50C07C39/10
CPCC07C37/50C07C39/10
Inventor 张基明杨长满周明华黄泽琦胡敬
Owner 遵义市倍缘化工有限责任公司