What molecule am I?
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鈥�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聽聽(M. Nierenstein, 1934) and 鈥�鈥� (O. Th. Schmidt, 1956).聽
Tannic acid聽hazard information
| GHS* classification:聽not a hazardous substance |
MOTW update
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Tannic acid聽fast facts
| CAS Reg. No. | 1401-55-4 |
| Molar mass | 1701.2 g/mol聽 |
| Empirical formula | C76H52O46 |
| Appearance | Light yellow to tan solid |
| Boiling point | 218 潞C (dec.) |
| Water solubility | 2850 g/L* |
*Some sources report 250 g/L.
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