Gallic Acid

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Gallic Acid (Wikipedia)
Gallic acid
Gallic acid.svg
Ácido gálico.png
IUPAC name
3,4,5-Trihydroxybenzoic acid
Other names
Gallic acid
149-91-7 YesY
5995-86-8 (monohydrate) N
ChEBI CHEBI:30778 YesY
ChEMBL ChEMBL288114 YesY
ChemSpider 361 YesY
EC Number 205-749-9
Jmol 3D image Interactive graph
KEGG C01424 YesY
PubChem 370
RTECS number LW7525000
UNII 632XD903SP YesY
Molar mass 170.12 g/mol
Appearance White, yellowish-white, or
pale fawn-colored crystals.
Density 1.694 g/cm3 (anhydrous)
Melting point 260 °C (500 °F; 533 K)
1.19 g/100 mL, 20°C (anhydrous)
1.5 g/100 mL, 20 °C (monohydrate)
Solubility soluble in alcohol, ether, glycerol, acetone
negligible in benzene, chloroform, petroleum ether
log P 0.70
Acidity (pKa) COOH: 4.5, OH: 10.
Main hazards Irritant
Safety data sheet External MSDS
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentineReactivity (yellow): no hazard codeSpecial hazards (white): no codeNFPA 704 four-colored diamond
Lethal dose or concentration (LD, LC):
5000 mg/kg (rabbit, oral)
Related compounds
carboxylic acids
Related compounds
Benzoic acid, Phenol, Pyrogallol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Gallic acid is a trihydroxybenzoic acid, a type of phenolic acid, a type of organic acid, also known as 3,4,5-trihydroxybenzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. The chemical formula is C6H2(OH)3COOH. Gallic acid is found both free and as part of hydrolyzable tannins. The gallic acid groups are usually bonded to form dimers such as ellagic acid. Hydrolysable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins respectively.

Gallic acid forms intermolecular esters (depsides) such as digallic and trigallic acid, and cyclic ether-esters (depsidones).

Gallic acid is commonly used in the pharmaceutical industry. It is used as a standard for determining the phenol content of various analytes by the Folin-Ciocalteau assay; results are reported in gallic acid equivalents. Gallic acid can also be used as a starting material in the synthesis of the psychedelic alkaloid mescaline.

The name is derived from oak galls, which were historically used to prepare tannic acid. Despite the name, gallic acid does not contain gallium. Salts and esters of gallic acid are termed "gallates".

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