| Octane[1][2] | |
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Octane |
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Other names
n-Octane |
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| Identifiers | |
| CAS number | 111-65-9 |
| PubChem | 356 |
| ChemSpider | 349 |
| DrugBank | DB02440 |
| KEGG | C01387 |
| ChEBI | CHEBI:17590 |
| ChEMBL | CHEMBL134886 |
| RTECS number | RG8400000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C8H18 |
| Molar mass | 114.23 g mol−1 |
| Appearance | Colorless liquid |
| Density | 0.703 g/mL |
| Melting point |
−57 °C, 216 K, -71 °F |
| Boiling point |
125.52 °C, 399 K, 258 °F |
| Solubility in water | Immiscible |
| Viscosity | 0.542 cP at 20 °C |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−250 kJ/mol |
| Std enthalpy of combustion ΔcH |
−5074.2 kJ/mol |
| Hazards | |
| EU classification | Flammable (F) Harmful (Xn) Dangerous for the environment (N) |
| R-phrases | R11 R38 R50/53 R65 R67 |
| S-phrases | (S2) S9 S16 S29 S33 S60 S61 S62 |
| Flash point | 13 °C |
| Autoignition temperature |
220 °C |
| Related compounds | |
| Related alkanes | Heptane 2,2,4-Trimethylpentane |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Octane is a hydrocarbon and an alkane with the chemical formula C8H18, and the condensed structural formula CH3(CH2)6CH3. Octane has many structural isomers that differ by the amount and location of branching in the carbon chain. One of these isomers, 2,2,4-trimethylpentane (isooctane) is used as one of the standard values in the octane rating scale.
As with all low-molecular weight hydrocarbons, octane and its isomers are very flammable. It and its isomers are components of gasoline (petrol).
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"Octane" is colloquially used as a short form of "octane rating" (named for the ability of octane's branched-chain isomers, especially isooctane, to reduce engine knock), particularly in the expression "high octane". However, components of gasoline other than isomers of octane can also contribute to a high octane rating, while some isomers of octane can lower it, and n-octane itself has a negative octane rating.[3]
Octane became well known in American popular culture in the mid- and late-sixties, when gasoline companies boasted of "high octane" levels in their gasoline in advertisements.
These commercials disappeared by the time of the 1973 Oil Crisis, which spared gasoline companies the need to compete via advertising. "Octane" was rarely cited in non-technical contexts over the next two decades.
The compound adjective "high-octane" was apparently first used in its figurative sense (i.e., without reference to gasoline) in a book review of Michael Crichton's novel Jurassic Park (1990), which appeared in the newspaper New York Newsday. The review by Gregory Feeley called the novel "intellectually provocative, high-octane entertainment", and was quoted the following year in the front matter of the novel's paperback edition, which sold more than 15 million copies in the United States. By the mid-nineties, the phrase was commonly being used as an intensifier and has apparently found a place in modern English vernacular.
Octane has 18 structural isomers (24 including stereoisomers):
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