Octane

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For the gasoline rating system, see octane rating. For other uses, see Octane (disambiguation).
Octane
IUPAC name

Octane[1]

Identifiers
CAS number 111-65-9 YesY
PubChem 356
ChemSpider 349 YesY
EC number 203-892-1
UN number 1262
DrugBank DB02440
KEGG C01387 YesY
MeSH octane
ChEBI CHEBI:17590 N
ChEMBL CHEMBL134886 YesY
RTECS number RG8400000
Beilstein Reference 1696875
Gmelin Reference 82412
3DMet B00281
Jmol-3D images Image 1
Properties
Molecular formula C8H18
Molar mass 114.23 g mol−1
Appearance Colorless liquid
Odor Gasoline-like
Density 0.703 g cm−3
Melting point −57.1 to −56.6 °C; −70.9 to −69.8 °F; 216.0 to 216.6 K
Boiling point 125.1 to 126.1 °C; 257.1 to 258.9 °F; 398.2 to 399.2 K
Solubility in water 0.007 mg dm−3 (at 20°C)
log P 4.783
Vapor pressure 1.47 kPa (at 20.0 °C)
kH 29 nmol Pa−1 kg−1
Refractive index (nD) 1.398
Viscosity 542 μPa s (at 20 °C)
Thermochemistry
Std enthalpy of
formation ΔfHo298		 −252.1–−248.5 kJ mol−1
Std enthalpy of
combustion ΔcHo298		 −5.53–−5.33 MJ mol−1
Standard molar
entropy So298		 361.20 J K−1 mol−1
Specific heat capacity, C 255.68 J K−1 mol−1
Hazards
GHS pictograms
GHS signal word DANGER
GHS hazard statements H225, H304, H315, H336, H410
GHS precautionary statements P210, P261, P273, P301+310, P331
EU Index 601-009-00-8
EU classification F Xn N
R-phrases R11, R38, R50/53, R65, R67
S-phrases (S2), S16, S29, S33
NFPA 704
3
1
0
Flash point 13.0 °C; 55.4 °F; 286.1 K
Autoignition temperature 220.0 °C; 428.0 °F; 493.1 K
Explosive limits 0.96–6.5%
Related compounds
Related alkanes
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 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 and 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.[2]

Metaphorical use

Octane became well known in American popular culture in the mid- and late 1960s, when gasoline companies boasted of "high octane" levels in their gasoline advertisements.

These commercials disappeared by the time of the 1973 Oil Crisis, which spared gasoline companies the need to compete in advertising. "Octane" was rarely cited in non-technical contexts over the next two decades.

The compound adjective "high-octane" was 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-1990s, the phrase was commonly being used as an intensifier and has found a place in modern English vernacular.

Isomers

Octane has 18 structural isomers (24 including stereoisomers):

References

  1. ↑ "octane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification and Related Records. Retrieved 6 January 2012. 
  2. ↑ eejit's guides – Octane ratings explained

External links

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