Gallic acid
From Wikipedia, the free encyclopedia
| 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 (pKa) | COOH: 4.5, OH: 10. |
| Chiral rotation [α]D | ?° |
| Structure | |
| Crystal structure | ? |
| Dipole moment | ? D |
| Hazards | |
| MSDS | External MSDS] |
| Main hazards | Irritant |
| NFPA 704 |
0
1
0
|
| 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) 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)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 damanging manuscripts for future study.
[edit] See also
- Pyrogallol
- Syringol
- Syringaldehyde
[edit] External link
[edit] References
- LD Reynolds and NG Wilson, “Scribes and Scholars” 3rd Ed. Oxford: 1991. pp193–4.
