Tannic acid

About Tannic acid

Name  Tannic acid
Synonyms  Gallotannic acid; Gallotannin; Galloylglucose; Glycerite; Quebracho;
                  Tannins
Molecular Formula  C76H52O46
Molecular Weight  1701.22
CAS Registry Number  1401-55-4
EINECS  215-753-2
  Tannic acid, a specific commercial form of tannin, is a polyphenol. Its weak acidity (pKa a
round 6) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, but in fact it contains a mixture of related compounds. Its structure is based mainly on glucose esters of gallic acid. It is a yellow to light brown amorphous powder which is highly soluble in water; one gram dissolves in 0.35 mL of water.
Tannic acid is a basic ingredient in the chemical staining of wood. The tannic acid or tannin is already present in woods like oak, walnut, and mahogany. Tannic acid can be applied to woods low in tannin so chemical stains that require tannin content will react. The presence of tannic acid in the bark of redwood (Sequoia) is a strong natural defense against wildfire, decomposition and infestation by certain insects such as woodboring beetles. It is found in the