Tannic Acid ACS Reagent, CAS 1401-55-4

Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity (pK_a 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. Tannic acid is a light yellow to tan solid with a faint odor. Sinks and mixes with water.