Preparation of Gallic Acid from Tea Leaves and other Tannin Containing Materials

Preparation of Gallic Acid from Tea Leaves and other Tannin Containing Materials 

Robert J. Turner, Ferguson, Robert D. Rands, Jr., Greendale, Montanna April 19, 1952 

The gallic acid can be isolated by crystallizing it directly from the hydrolysis mixture but a purer and more desirable produce is obtained by extracting it from the liquor with a water-immiscible solvent. 

Illustrative of suitable water-immiscible solvents for gallic acid are methyl isobutyl ketone, methyl isobutyl carbinol, mixtures of isomeric amyl alcohols, isoamyl alcohol, and cyclohexanone. 

As a further embodiment of this invention, the amount of water required for the hydrolysis of the tannin-containing materials can be reduced by replacing part of it with a portion of the water-immiscible solvent, in which case less solvent is required in the subsequent extraction step. 

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