Catechol
Catechol (/ˈkætɪtʃɒl/ or /ˈkætɪkɒl/), also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound with the molecular formula C6H4(OH)2. It is the ortho isomer of the three isomeric benzenediols. This colorless compound occurs naturally in trace amounts. It was first discovered by destructive distillation of the plant extract catechin. About 20,000 tonnes of catechol are now synthetically produced annually as a commodity organic chemical, mainly as a precursor to pesticides, flavors, and fragrances.
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| Names | |||
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| Preferred IUPAC name
Benzene-1,2-diol | |||
| Other names
Pyrocatechol 1,2-Benzenediol 2-Hydroxyphenol 1,2-Dihydroxybenzene o-Benzenediol o-Dihydroxybenzene | |||
| Identifiers | |||
3D model (JSmol) |
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| 471401 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| DrugBank | |||
| ECHA InfoCard | 100.004.025 | ||
| EC Number |
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| 2936 | |||
| KEGG | |||
PubChem CID |
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| RTECS number |
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| UNII | |||
CompTox Dashboard (EPA) |
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| Properties | |||
| C6H6O2 | |||
| Molar mass | 110.112 g·mol−1 | ||
| Appearance | white to brown feathery crystals | ||
| Odor | faint, phenolic odor | ||
| Density | 1.344 g/cm3, solid | ||
| Melting point | 105 °C (221 °F; 378 K) | ||
| Boiling point | 245.5 °C (473.9 °F; 518.6 K) (sublimes) | ||
| 430 g/L | |||
| Solubility | very soluble in pyridine soluble in chloroform, benzene, CCl4, ether, ethyl acetate | ||
| log P | 0.88 | ||
| Vapor pressure | 20 Pa (20 °C) | ||
| Acidity (pKa) | 9.45, 12.8 | ||
| −6.876×10−5 cm3/mol | |||
Refractive index (nD) |
1.604 | ||
| 2.62±0.03 D | |||
| Structure | |||
| monoclinic | |||
| Thermochemistry | |||
Std enthalpy of formation (ΔfH⦵298) |
−354.1 kJ·mol−1 | ||
Enthalpy of fusion (ΔfH⦵fus) |
22.8 kJ·mol−1 (at melting point) | ||
| Hazards | |||
| GHS labelling: | |||
| Danger | |||
| H301, H311, H315, H317, H318, H332, H341 | |||
| P261, P301, P302, P305, P310, P312, P330, P331, P338, P351, P352 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | 127 °C (261 °F; 400 K) | ||
| 510 °C (950 °F; 783 K) | |||
| Explosive limits | 1.4%–? | ||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) |
300 mg/kg (rat, oral) | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible) |
none | ||
REL (Recommended) |
TWA 5 ppm (20 mg/m3) [skin] | ||
IDLH (Immediate danger) |
N.D. | ||
| Safety data sheet (SDS) | Sigma-Aldrich | ||
| Related compounds | |||
Related benzenediols |
Resorcinol Hydroquinone | ||
Related compounds |
1,2-benzoquinone | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |||
Catechol occurs as feathery white crystals that are very rapidly soluble in water.
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