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Gallic acid
Gallic acid
General
Systematic name	3,4,5-hydroxybenzoic acid
Other names	Gallic acid
Molecular formula	C7H6O5
SMILES	Oc1cc(cc(O)c1O)C(O)=O
Molar mass	170.12 g/mol
Appearance	White, yellowish-white, or pale fawn-colored crystals.
CAS number	[149-91-7] (Anhydrous) [5995-86-8] (Monohydrate)
Properties
Density and phase	1.7 g/cm3 (anhydrous)
Solubility in water	1.1g/100ml water @ 20°C (anhydrous) 1.5g/100ml water @ 20°C (monohydrate)
Melting point	250°C (523 K)
Boiling point	?°C (? K)
Acidity (p''K''a)	COOH: 4.5, OH: 10.
Structure
Crystal structure	?
Dipole moment	? D
Hazards
MSDS	External MSDS]
Main hazards	Irritant
NFPA 704
Flash point	?°C
R/S statement	R: ? S: ?
RTECS number	?
Supplementary data page
Structure and properties	''n'', εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related phenols, carboxylic acids	?
Related compounds	Benzoic acid, Phenol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

'Gallic acid' is an 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)₃CO₂H. Gallic acid is found both free and as part of tannins. It is commonly used in the pharmaceutical industry. Gallic acid can also be used to synthesize the hallucinogenic alkaloid, mescaline, also known as 3,4,5-trimethoxyphenethylamine.
Salts and esters of gallic acid are termed gallates.
Gallic acid was one of the substances used by Angelo Mai among other early investigators of palimpsests to clear the top layer of text off and reveal hidden manuscripts underneath. Mai was the first to employ it, but did so "with a heavy hand," often damaging manuscripts for future study.

Contents

See also

External link

References

See also

★ Pyrogallol

★ Syringol

★ Syringaldehyde

External link

★ King's American Dispensatory (1898) entry on Gallic acid

References

★ LD Reynolds and NG Wilson, “Scribes and Scholars” 3rd Ed. Oxford: 1991. pp193–4.