- Octane
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Octane[1][2] 
OctaneOther namesn-OctaneIdentifiers 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 - CCCCCCCC
- InChI=1S/C8H18/c1-3-5-7-8-6-4-2/h3-8H2,1-2H3
Key: TVMXDCGIABBOFY-UHFFFAOYSA-N
InChI=1/C8H18/c1-3-5-7-8-6-4-2/h3-8H2,1-2H3
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 ΔfHo298−250 kJ/mol Std enthalpy of
combustion ΔcHo298−5074.2 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
temperature220 °C Related compounds Related alkanes Heptane
2,2,4-Trimethylpentane
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)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).
Contents
Use of the term in gasoline
"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]
Metaphorical use
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.[citation needed] 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.
Isomers
Octane has 18 structural isomers (24 including stereoisomers):
- Octane (n-octane)
- 2-Methylheptane
- 3-Methylheptane (2 enantiomers)
- 4-Methylheptane
- 3-Ethylhexane
- 2,2-Dimethylhexane
- 2,3-Dimethylhexane (2 enantiomers)
- 2,4-Dimethylhexane (2 enantiomers)
- 2,5-Dimethylhexane
- 3,3-Dimethylhexane
- 3,4-Dimethylhexane (2 enantiomers + 1 meso compound)
- 3-Ethyl-2-methylpentane
- 3-Ethyl-3-methylpentane
- 2,2,3-Trimethylpentane (2 enantiomers)
- 2,2,4-Trimethylpentane (isooctane)
- 2,3,3-Trimethylpentane
- 2,3,4-Trimethylpentane
- 2,2,3,3-Tetramethylbutane
References
External links
- International Chemical Safety Card 0933
- NIOSH Pocket Guide to Chemical Hazards 0470
- Phytochemical database entry
Alkanes Higher alkanes · List of alkanes Categories:- Alkanes
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