1-Hexanol (IUPAC name hexan-1-ol) is an organic alcohol with a six-carbon chain and a condensed structural formula of CH3(CH2)5OH. This colorless liquid is slightly soluble in water, but miscible with diethyl ether and ethanol. Two additional straight chain isomers of 1-hexanol, 2-hexanol and 3-hexanol, exist, both of which differing by the location of the hydroxyl group. Many isomeric alcohols have the formula C6H13OH. It is used in the perfume industry.
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| Names | |||
|---|---|---|---|
| Preferred IUPAC name Hexan-1-ol[1] | |||
| Other names amyl carbinol | |||
| Identifiers | |||
3D model (JSmol) | |||
| 969167 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| ECHA InfoCard | 100.003.503 | ||
| EC Number |
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| MeSH | 1-Hexanol | ||
PubChem CID | |||
| RTECS number |
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| UNII | |||
| UN number | 2282 | ||
CompTox Dashboard (EPA) | |||
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| Properties | |||
| C6H14O | |||
| Molar mass | 102.177 g·mol−1 | ||
| Appearance | colorless liquid | ||
| Density | 0.82 g cm−3 (at 20 °C)[2] | ||
| Melting point | −45 °C (−49 °F; 228 K)[2] | ||
| Boiling point | 157 °C (315 °F; 430 K)[2] | ||
| 5.9 g/L (at 20 °C)[2] | |||
| log P | 1.858 | ||
| Vapor pressure | 100 Pa (at 25.6 °C) | ||
Refractive index (nD) | 1.4178 (at 20 °C) | ||
| Thermochemistry | |||
Heat capacity (C) | 243.2 J K−1 mol−1 | ||
Std molar entropy (S⦵298) | 287.4 J K−1 mol−1 | ||
Std enthalpy of formation (ΔfH⦵298) | −377.5 kJ mol−1 | ||
Std enthalpy of combustion (ΔcH⦵298) | −3.98437 MJ mol−1 | ||
| Hazards | |||
| GHS labelling: | |||
 | |||
| Warning | |||
| H302 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | 59 °C (138 °F; 332 K) | ||
| 293 °C (559 °F; 566 K) | |||
| Safety data sheet (SDS) | ICSC 1084 | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
Preparation
Hexanol is produced industrially by the oligomerization of ethylene using triethylaluminium followed by oxidation of the alkylaluminium products.[3] An idealized synthesis is shown:
- Al(C2H5)3 + 6C2H4 → Al(C6H13)3
- Al(C6H13)3 + 1+1⁄2O2 + 3H2O → 3HOC6H13 + Al(OH)3
The process generates a range of oligomers that are separated by distillation.
Alternative methods
Another method of preparation entails hydroformylation of 1-pentene followed by hydrogenation of the resulting aldehydes. This method is practiced in industry to produce mixtures of isomeric C6-alcohols, which are precursors to plasticizers.[3]
In principle, 1-hexene could be converted to 1-hexanol by hydroboration (diborane in tetrahydrofuran followed by treatment with hydrogen peroxide and sodium hydroxide):
This method is instructive and useful in laboratory synthesis but of no practical relevance because of the commercial availability of inexpensive 1-hexanol from ethylene.
Occurrence in nature
1-Hexanol is believed to be a component of the odour of freshly mown grass. Alarm pheromones emitted by the Koschevnikov gland of honey bees contain 1-hexanol. It also is partly responsible for the fragrance of strawberries.
See also
- Cis-3-Hexenal, another volatile organic compound, is also considered responsible for the freshly mowed grass odor.