Tannic acid

January 16, 2018
I’m associated with wine and leather.
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Image of Tannic acid 3D Image of Tannic acid

Tannins are polyphenolic biomolecules with carbohydrate backbones that are found in in a wide range of plants. Tannic acid is a specific tannin that formally contains 10 galloyl (3,4,5-trihydroxyphenyl) units surrounding a glucose center. Commercial tannic acid, however, consists of molecules with 2–12 galloyl moieties.

Tannic acid contains no carboxyl groups, but is weakly acidic because of the multiplicity of phenolic hydroxyls. The hydroxyls also cause it to be extremely soluble in water. All regulatory authorities classify it as a nonhazardous substance.

As the name implies, tannins are used in leather tanning. Other commercial uses are in dyeing, ink manufacture, paper sizing, food and wine processing, and production of gallic acid and pyrogallol.

Early reviews of tannins and tannic acid include The Natural Organic Tannins (M. Nierenstein, 1934) and “Gallotannine und Ellagen-gerbstoffe” (O. Th. Schmidt, 1956). 

Tannic acid hazard information

GHS* classification: not a hazardous substance

MOTW update

Carfilzomib was the Molecule of the Week for December 10, 2012. It is a selective proteasome inhibitor that is used to treat patients with relapsed, refractory multiple myeloma. But recently, data analysis of 24 clinical trials on carfilzomib revealed high incidence of adverse cardiac events, many of which were severe or life-threatening.

Tannic acid fast facts

CAS Reg. No.1401-55-4
Molar mass1701.2 g/mol 
Empirical formulaC76H52O46
AppearanceLight yellow to tan solid
Boiling point218 ºC (dec.)
Water solubility2850 g/L*

*Some sources report 250 g/L.

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