Tannic acid is a specific commercial form of tannin, a type of polyphenol. Its weak acidity (pKa around 10) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which corresponds with decagalloyl glucose, but in fact it is a mixture of polygalloyl glucoses or polygalloyl quinic acid esters with the number of galloyl moieties per molecule ranging from 2 up to 12 depending on the plant source used to extract the tannic acid. Commercial tannic acid is usually extracted from any of the following plant part: Tara pods (Caesalpinia spinosa), gallnuts from Rhus semialata or Quercus infectoria or Sicilian Sumac leaves (Rhus coriaria).

Basic ingredient in the chemical staining of wood
Common mordant used in the dyeing process for cellulose fibers such as cotton
Used in the conservation of ferrous (iron based) metal objects to passivate and inhibit corrosion
Used in food applications such as processing aids in beer clarification

Molecular Formula: C76H52O46
Molecular Weight: 1701.20
Solubility in water (% weight): Soluble in water
Flash Point: 199°C
Melting Point: 218°C
Heavy metals (as Pb): <0.00003%
Arsenic (As): <0.0003%
Loss on drying at 105C: 3.28%
Sulphated Ash: 0.079%
Alcohol: Extracted

Hazard Phrases: Not considered harmful under normal laboratory conditions

Cas No: 1401-55-4
Einecs No: 215-753-2