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| Gallic acid | |
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| IUPAC name | 3,4,5-hydroxybenzoic acid |
| Other names | Gallic acid |
| Identifiers | |
| CAS number | [149-91-7] (Anhydrous) [5995-86-8] (Monohydrate) |
| SMILES |
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| Properties | |
| Molecular formula | C7H6O5 |
| Molar mass | 170.12 g/mol |
| Appearance | White, yellowish-white, or pale fawn-colored crystals. |
| Density | 1.7 g/cm3 (anhydrous) |
| Melting point |
250°C (523 K) |
| Boiling point |
(? K) |
| Solubility in water | 1.1g/100ml water @ 20°C (anhydrous) 1.5g/100ml water @ 20°C (monohydrate) |
| Acidity (pKa) | COOH: 4.5, OH: 10. |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Irritant |
| Related compounds | |
| Related compounds | Benzoic acid, Phenol |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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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)3COOH. Gallic acid is found both free and as part of tannins. Salts and esters of gallic acid are termed gallates. Despite its name, it does not contain gallium.
Gallic acid is commonly used in the pharmaceutical industry.citation needed 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.[1] Gallic acid can also be used to synthesize the hallucinogenic alkaloid mescaline, also known as 3,4,5-trimethoxyphenethylamine.citation needed
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.citation needed
See also
References
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The references used in this article may be clearer with a different or consistent style of citation, footnoting, or external linking. This article has been tagged since September 2007. |
- LD Reynolds and NG Wilson, “Scribes and Scholars” 3rd Ed. Oxford: 1991. pp193–4.
- ^ Andrew Waterhouse. "Folin-Ciocalteau Micro Method for Total Phenol in Wine". UC Davis.
External links
