A method for preparing pyrogallic acid by atmospheric pressure two-phase catalysis

A pyrogallic acid, catalyzed preparation technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of uneven heating of materials, low conversion rate, and reduced equipment life cycle, etc., to achieve a solution Crystallization is difficult to dry, promotes the reaction equilibrium shift, and improves the yield

Active Publication Date: 2019-03-05
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

Biological decarboxylation method, decarboxylase is not easy to prepare, the activity is not high, most of them need anaerobic conditions, and the equipment conditions are relatively large; atmospheric pressure catalytic decarboxylation method and reduced pressure catalytic decarboxylation method are more common and mature, but the material is heated unevenly, which wastes energy , to reduce the service life of the equipment, the catalyst used is not easy to separate, causing pollution; the normal pressure catalytic decarboxylation method, the conversion rate is not high, and it is easy to cause waste of raw materials; while the high pressure catalytic decarboxylation method has a high yield, which is suitable for equipment with pressure and temperature resistance The requirements are relatively high, the general temperature is above 150°C, the pressure is ≥10MPa, and there are great safety hazards

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] (1) Add 80ml of water, 40ml of isoamyl alcohol, and 10g of gallic acid into the reaction vessel, add 1g of tetrabutylammonium chloride, heat up to 80-90°C, and react for 5 hours, TLC traces to no gallic acid spots, down to room temperature, layered;

[0019] (2), the isoamyl alcohol layer was washed 3 times with water, the combined water layer was incorporated into the water phase of the previous step (1), 120 ml of ethyl acetate was added, and extracted 3 times; the combined ethyl acetate layer was added with 40 ml of chloroform, Crystallize at 5-10°C, filter and bake to obtain 5.29 g of pyrogallic acid solid, with a yield of 52.9%, a liquid phase purity of ≥98.5%, and a residue of ≤0.1%.

Embodiment 2

[0021] (1) Add 70ml of water, 60ml of n-butanol, and 10g of gallic acid into the reaction vessel, add 1.5g of tetrabutylammonium bromide, raise the temperature to 80-90°C, and react for 5.5 hours, TLC traces to the absence of gallic acid Spotted, cooled to room temperature, layered;

[0022] (2), the n-butanol layer was washed 4 times with water, the combined water layer was incorporated into the water phase of the previous step (1), 120 ml of ethyl acetate was added, and extracted 4 times; the ethyl acetate layer was combined, and dichloromethane was added 35ml, crystallized at 5-10°C, filtered and baked to obtain 5.26g of pyrogallic acid solid, yield 52.6%, liquid phase purity ≥ 98.9%, residue ≤ 0.1%.

Embodiment 3

[0024] (1) Add 100ml of water, 60ml of isoamyl alcohol, and 10g of gallic acid into the reaction vessel, add 1.8g of tetrabutylammonium iodide, heat up to 80-90°C, and react for 6 hours. TLC traces to no gallic acid spots , down to room temperature, layered;

[0025] (2), the isoamyl alcohol layer was washed 4 times with water, the combined water layer was incorporated into the water phase of the previous step (1), 120 ml of ethyl acetate was added, and extracted 3 times; the combined ethyl acetate layer was added with 35 ml of chloroform, Crystallize at 5-10°C, filter and bake to obtain 5.16 g of pyrogallic acid solid, with a yield of 51.6%, a liquid phase purity of ≥98.9%, and a residue of ≤0.1%.

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Abstract

The invention discloses a method using biphasic catalysis to prepare pyrogallic acid under normal pressure. The method includes: using the mixed liquid of water and weak-polarity solvent as the solvent, adding a phase catalyst and gallic acid, performing reaction under normal pressure and 80-90 DEG C for 5-6 hours, performing TLC tracking until no gallic acid spots exist, cooling to room temperature, and performing layering; washing an organic layer with water for 3-4 times, and adding into the water phase obtained in the previous step; combining to obtain a water layer, extracting with ethyl acetate, and performing layering; combining the obtained ethyl acetate layer, adding an organic solvent A, cooling and crystallizing, and filtering and drying to obtain pyrogallic acid solid. The method has the advantages that the yield of the pyrogallic acid is not smaller than 51.6%, the liquid phase purity of the pyrogallic acid is not smaller than 98.5%, and residues are not larger than 0.1%; the reaction of the method is performed under normal pressure and 80-90 DEG C, and the method is low in equipment requirement and suitable for industrial production; the crystallizing of the method is performed in the organic solvent, easiness in drying is achieved, and the problem that the pyrogallic acid is hard to dry due to the fact that the product is crystalized in water can be solved.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a method for preparing pyrogallic acid by two-phase catalysis under normal pressure. Background technique [0002] Pyrogallic acid, that is, pyrogallol or pyrogallol, is white or yellow needle-like crystals, sublimates without decomposing when heated slowly, is easily oxidized, easily soluble in water, ethanol and ether, slightly soluble in benzene, diethyl ether Toluene, chloroform, carbon disulfide and other solvents. It is highly irritating to the skin and mucous membranes. When pyrogallic acid is swallowed, it can cause severe damage to the digestive tract, liver and kidneys. Pyrogallic acid is a chemical reagent and chemical raw material with multiple uses, widely used in pharmaceutical synthesis, dyes, food, pesticides and electronic products, etc. Analytical reagents, etc., and in some fields are irreplaceable by other products. [0003] There are many preparation meth...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C37/50C07C39/10
CPCC07C37/50C07C39/10
Inventor 张基明杨长满杨金明蒋家均胡敬
Owner 遵义市倍缘化工有限责任公司
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