Octane
Encyclopedia
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).
" (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.
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.
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
and an alkane
Alkane
Alkanes are chemical compounds that consist only of hydrogen and carbon atoms and are bonded exclusively by single bonds without any cycles...
with the chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
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
2,2,4-Trimethylpentane
2,2,4-Trimethylpentane, also known as isooctane, iso-octane, is an organic compound with the formula 3CCH2CH2. It is one of several isomers of octane . This particular isomer is the standard for 100 point on the octane rating scale...
(isooctane) is used as one of the standard values in the octane rating
Octane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...
scale.
As with all low-molecular weight hydrocarbons, octane and its isomers are very flammable. It and its isomers are components of gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
(petrol).
Use of the term in gasoline
"Octane" is colloquially used as a short form of "octane ratingOctane rating
Octane rating or octane number is a standard measure of the anti-knock properties of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating...
" (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.
Metaphorical use
Octane became well known in American popular culture in the mid- and late-sixties, when gasolineGasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
companies boasted of "high octane" levels in their gasoline in advertisements.
These commercials disappeared by the time of the 1973 Oil Crisis
1973 oil crisis
The 1973 oil crisis started in October 1973, when the members of Organization of Arab Petroleum Exporting Countries or the OAPEC proclaimed an oil embargo. This was "in response to the U.S. decision to re-supply the Israeli military" during the Yom Kippur war. It lasted until March 1974. With the...
, 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
Michael Crichton
John Michael Crichton , best known as Michael Crichton, was an American best-selling author, producer, director, and screenwriter, best known for his work in the science fiction, medical fiction, and thriller genres. His books have sold over 200 million copies worldwide, and many have been adapted...
's novel Jurassic Park (1990), which appeared in the newspaper New York Newsday
Newsday
Newsday is a daily American newspaper that primarily serves Nassau and Suffolk counties and the New York City borough of Queens on Long Island, although it is sold throughout the New York metropolitan area...
. 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-Methylheptane2-Methylheptane2-Methylheptane is a branched alkane isomeric to octane. Its structural formula is 2CH4CH3.-External links:*...
- 3-Methylheptane3-Methylheptane3-Methylheptane is a branched alkane isomeric to octane. Its structural formula is CH3CH2CHCH2CH2CH2CH3. It has one stereocenter.Its refractive index is 1.398 .-External links:**...
(2 enantiomers) - 4-Methylheptane
- 3-Ethylhexane
- 2,2-Dimethylhexane
- 2,3-Dimethylhexane2,3-Dimethylhexane2,3-dimethylhexane is an structural isomer of octane....
(2 enantiomers) - 2,4-Dimethylhexane (2 enantiomers)
- 2,5-Dimethylhexane2,5-Dimethylhexane2,5-Dimethylhexane is a branched alkane used in the aviation industry in low revolutions per minute helicopters. As an isomer of octane, the boiling point is very close to that of octane, but can in pure form be slightly lower. 2,5-Dimethylhexane is moderately toxic....
- 3,3-Dimethylhexane
- 3,4-Dimethylhexane (2 enantiomers + 1 meso compoundMeso compoundA meso compound or meso isomer is a non-optically active member of a set of stereoisomers, at least two of which are optically active. This means that despite containing two or more stereocenters it is not chiral. A meso compound is superimposable on its mirror image, and it does not produce a ""...
) - 3-Ethyl-2-methylpentane
- 3-Ethyl-3-methylpentane
- 2,2,3-Trimethylpentane (2 enantiomers)
- 2,2,4-Trimethylpentane2,2,4-Trimethylpentane2,2,4-Trimethylpentane, also known as isooctane, iso-octane, is an organic compound with the formula 3CCH2CH2. It is one of several isomers of octane . This particular isomer is the standard for 100 point on the octane rating scale...
(isooctane) - 2,3,3-Trimethylpentane2,3,3-Trimethylpentane2,3,3-Trimethylpentane is a chemical compound in the family of hydrocarbons which has a formula of C8H18. It is an isomer of octane....
- 2,3,4-Trimethylpentane2,3,4-Trimethylpentane2,3,4-Trimethylpentane is a branched alkane. It is one of the isomers of octane.-External links:* at rdchemicals.com* at chemicalbook.com* at environmentalchemistry.com* at lookchem.com...
- 2,2,3,3-Tetramethylbutane