CAS number 111-65-9 YesY
PubChem 356
ChemSpider 349 YesY
DrugBank DB02440
KEGG C01387 YesY
RTECS number RG8400000
Jmol-3D images Image 1
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
Std enthalpy of
−250 kJ/mol
Std enthalpy of
−5074.2 kJ/mol
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
220 °C
Related compounds
Related alkanes Heptane
 N (verify) (what is: YesY/N?)
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).


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.


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


External links

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • octane — [ ɔktan ] n. m. • 1874; de oct et suff. ane ♦ Chim. Hydrocarbure saturé (C8H18) de la série des paraffines, à nombreux isomères (⇒ isooctane). Cour. Indice d octane : échelle conventionnelle caractérisant le pouvoir antidétonant d un carburant. ● …   Encyclopédie Universelle

  • Octane SB — Octane (album) Pour les articles homonymes, voir Octane (homonymie). Octane Spock s Beard Date de sortie Mars 2005 Style Rock progressif …   Wikipédia en Français

  • Octane — steht für: Octane – Grausamer Verdacht, ein Film SGI Octane eine Computerplattform von SGI Octane (Chemie) eine Stoffgruppe der Alkane mit der Summenformel C8H18 Diese Seite ist eine Begriffsklärung …   Deutsch Wikipedia

  • Octane — álbum de estudio de Spock s Beard Publicación 1 de Febrero de 2005 Género(s) Rock Progresivo Duración 55:54 Discográfica …   Wikipedia Español

  • Octane —   [zu lateinisch octo »acht«], Singular Octan das, s, flüssige Kohlenwasserstoffe aus der Gruppe der Alkane mit der Summenformel C8H18. Neben dem geradkettigen n Octan existieren 17 Isomere mit verzweigten Kohlenstoffketten (Isooctane) …   Universal-Lexikon

  • octane — (n.) hydrocarbon of the methane series, 1872, coined from octo (see OCTA (Cf. octa )) + ANE (Cf. ane); so called because it has eight carbon atoms. A fuel s octane rating, in reference to its anti knocking quality, is attested from 1932 …   Etymology dictionary

  • octane — oc tane ([o^]k t[=a]n), n. [See {Octa }] (Chem.) Any one of a group of metametric hydrocarbons ({C8H18}) of the methane (paraffin) series. The most important is a colorless, volatile, inflammable liquid, found in petroleum, and a constituent of… …   The Collaborative International Dictionary of English

  • octane — ► NOUN Chemistry ▪ a liquid hydrocarbon present in petroleum spirit …   English terms dictionary

  • octane — [äk′tān΄] n. [ OCT + ANE] an oily alkane, C8H18, occurring in petroleum, or any of a group of isomers of this substance …   English World dictionary

  • Octane — Pour les articles homonymes, voir Octane (homonymie). Octane …   Wikipédia en Français

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.