Octane

For the gasoline rating system, see octane rating. For other uses, see Octane (disambiguation).
Octane
Skeletal formula of octane
Skeletal formula of octane with all implicit carbons shown, and all explicit hydrogens added
Ball-and-stick model of octane
Space-filling model of octane
Names
IUPAC name
Octane[1]
Identifiers
3DMet B00281
1696875
111-65-9 Yes
ChEBI CHEBI:17590 
ChEMBL ChEMBL134886 Yes
ChemSpider 349 Yes
DrugBank DB02440 
EC number 203-892-1
82412
Jmol-3D images Image
KEGG C01387 Yes
MeSH octane
PubChem 356
RTECS number RG8400000
UN number 1262
Properties
Molecular formula
 C8H18
Molar mass 114.23 g·mol−1
Appearance Colorless liquid
Odor Odorless
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
0.007 mg dm−3 (at 20°C)
log P 4.783
Vapor pressure 1.47 kPa (at 20.0 °C)
29 nmol Pa−1 kg−1
1.398
Viscosity 542 μPa s (at 20 °C)
Thermochemistry
Specific
heat capacity (C)
 255.68 J K−1 mol−1
361.20 J K−1 mol−1
Std enthalpy of
formation (ΔfHo298)
 −252.1–−248.5 kJ mol−1
Std enthalpy of
combustion (ΔcHo298)
 −5.53–−5.33 MJ mol−1
Hazards
GHS pictograms
GHS signal word DANGER
H225, H304, H315, H336, H410
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
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasoline) Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
3
1
0
Flash point 13.0 °C (55.4 °F; 286.1 K)
220.0 °C (428.0 °F; 493.1 K)
Explosive limits 0.96–6.5%
Related compounds
Related alkanes
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 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.

Octane is a component of gasoline (petrol). As with all low molecular weight hydrocarbons, octane is volatile and very flammable.

Use of the term in gasoline

"Octane" is colloquially used as a short form of "octane rating" (an index of a fuel's ability to resist engine knock at high compression ratios, which is a characteristic of octane's branched-chain isomers, especially isooctane), 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" is recorded in a figurative sense from 1944.[3] By the mid-1990s, the phrase was commonly being used as an intensifier and has found a place in modern English vernacular.

"Octane" is a slang term for trihexyphenidyl, because of its similarity to its trade name Artane.

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
  3. ↑ Oxford English Dictionary.

External links