Isolation of Tannins
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Both hydrolysable and condensed tannins are highly soluble in water and alcohol but insoluble in organic solvents such as solvent ether, chloroform, and benzene. Tannin compounds can be easily extracted by water or alcohol.
Isolation
Both hydrolysable and condensed tannins are highly soluble
in water and alcohol but insoluble in organic solvents such as solvent ether,
chloroform, and benzene. Tannin compounds can be easily extracted by water or
alcohol. The general method for the extraction of tannic acid from various
galls is either with water-saturated ether, or with mixture of water, alcohol,
and ether. In such cases, free acids such as Gallic and ellagic acid go along
with ether, whereas true tannin gets extracted in water. If the drug consists
of chlorophyll or pigment, it may be removed by ether. After extraction, the
aqueous and ethereal layers are separately concentrated, dried, and subjected
to further isolation and purification using various separation techniques of
chromatography.
