Preparation of oligomer and monomer from tannin by catalytic hydrogen degradation

A technology for plant tannin and catalytic hydrogenolysis, which is applied in the preparation of organic compounds, organic chemistry methods, chemical instruments and methods, etc. Problems such as hydroxyl oxidation, loss of biological and chemical activity of products, etc., to achieve the effect of improving resource utilization and added value, less waste discharge, and high product value

Inactive Publication Date: 2005-02-23
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, chemical reagents such as acids, alkalis, and oxidants used in the above method are likely to cause equipment corrosion and environmental pollution; more importantly, the above method is difficult to avoid the oxidation of the active phenolic hydroxyl group of proanthocyanidin tannins, thus causing the product to lose its biological and chemical properties. active
For this reason, the existing tannin degradation modification method is not suitable for the preparation of proanthocyanidin oligomers and monomer products, as well as other biologically active products

Method used

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  • Preparation of oligomer and monomer from tannin by catalytic hydrogen degradation
  • Preparation of oligomer and monomer from tannin by catalytic hydrogen degradation
  • Preparation of oligomer and monomer from tannin by catalytic hydrogen degradation

Examples

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Effect test

Embodiment 1

[0033] Example 1: Preparation of oligomeric proanthocyanidins by extraction, fractionation and catalytic hydrogenolysis of larch proanthocyanidins

[0034] The first step: Larix proanthocyanidin extraction and classification

[0035]Air-dried larch bark is used as raw material, crushed into particles with a particle size of 1-15mm, and sieved to remove impurities. Then, weigh 10 kg of the above-mentioned materials, add 100 L of 70% volume ratio ethanol aqueous solution, and extract in an extraction tank at a temperature of 70±5°C for 4 hours under forced reflux with a pump, and then discharge. Remove the slag through coarse filtration, pump the resulting filtrate into a vacuum concentration tank, reclaim ethanol, discharge, and then filter, and the precipitated part is dried to obtain 736g reddish-brown powder, which is proanthocyanidin high polymer (LPE); in the filtrate Add petroleum ether or light oil, oscillate or stir, and let stand to separate layers to remove esters an...

Embodiment 2

[0038] Example 2: Preparation of oligomeric proanthocyanidins from larch extract by catalytic hydrogenolysis

[0039] Take 200g of larch extract (not treated with sulfurous acid), add 5g of Pd-C catalyst, add 1000ml of ethanol with a volume ratio of 55%, mix well, put it into an autoclave, feed hydrogen to make the air pressure 0.2MPa, and The temperature was 60°C, and the reaction was carried out for 4 hours under stirring. Stop heating, and when the temperature drops to room temperature, exhaust to normal pressure first, and take out the reaction product. Filter, concentrate under reduced pressure, and dry to obtain 135 g of the product (LPH). The obtained product was dissolved in water, and then extracted four times with ethyl acetate to obtain the extract layer. After drying, 70.7 g of reddish-brown oligomeric proanthocyanidin (LPHC) was obtained, accounting for about 52.37%; while the water layer of the raffinate phase was brown poly-proanthocyanidin (LPHW), weighing 26...

Embodiment 3

[0040] Example 3: Preparation of ellagic acid by catalytic hydrogenolysis of oak extracts

[0041] Take 100g of extract in a rubber bowl, add 2g of palladium-carbon catalyst, add 800ml of ethanol with a volume ratio of 45%, mix well, put it into an autoclave, feed hydrogen gas to make the pressure 10MPa, and react 4 at a temperature of 80°C under stirring. Hour. Stop heating, when the temperature drops to room temperature, exhaust to normal pressure first, take out the reaction product, heat to above 70°C, filter while hot to remove the residue, concentrate the filtrate under reduced pressure, cool, filter with suction, and wash the filter cake with distilled water 2 to 3 times and discard the filtrate. Then the filter cake was washed with pyridine to dissolve ellagic acid, and after several recrystallizations, 13.2 g of light yellow ellagic acid crystals were obtained.

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Abstract

A process for preparing oligomer or monomer from vegetative tannin includes such steps as immersing the plant rich in tannin in alcohol or ketone, extracting to obtain liquid extract, recovering solvent , filter, extractin in different solvents to obtain different components, catalytic hydrogendyzing to obtain coarse pdyphenol monomer and oligomer, and purifying to obtain oligoproanthocyaridin, ellagic acid, and gallic acid.

Description

1. Technical field [0001] The invention relates to a catalytic hydrogenolysis preparation method for degrading plant tannins into oligomers and monomer compounds. This method can be used to prepare oligomeric proanthocyanidins (OPC's) from condensed tannins (polymeric proanthocyanidins), and to prepare bioactive components of ellagic acid, gallic acid, and galloyl ester glucose from hydrolyzed tannins. It can also be used for The invention relates to the degradation modification of tannin extract or adhesive, which belongs to the field of fine chemical industry. 2. Background technology [0002] Plant tannin is a plant polyphenol secondary substance produced by plant secondary metabolism. It widely exists in plant leaves, wood, bark and fruit, and is a renewable green resource. For example, the tannin content in the bark of coniferous plants is as high as 20%-40%. Only this item has an annual output of hundreds of millions of tons in the world, so tannin is an important obj...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A23L33/105C07B35/06C07B61/00C07C51/377C07C65/03C07H13/08C07H15/18C09J11/06
Inventor 石碧杜晓
Owner SICHUAN UNIV
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