Editing Alkane (section)

===Fuels===
The dominant use of alkanes is as fuels. [[Propane]] and [[butane]], easily liquified gases, are commonly known as [[liquified petroleum gas]] (LPG).<ref>{{Cite web |url=http://www.ferrellgas.com/Resource_/PageResource/LA_Transit_Case_Study.pdf |title=Using propane as a fuel |access-date=27 November 2012 |archive-url=https://web.archive.org/web/20131012000108/http://ferrellgas.com/Resource_/PageResource/LA_Transit_Case_Study.pdf |archive-date=12 October 2013 |url-status=dead  }}</ref>  From [[pentane]] to [[octane]] the alkanes are highly volatile liquids. They are used as fuels in [[internal combustion engine]]s, as they vaporize easily on entry into the combustion chamber without forming droplets, which would impair the uniformity of the combustion. Branched-chain alkanes are preferred as they are much less prone to premature ignition, which causes [[Engine knocking|knocking]], than their straight-chain homologues. This propensity to premature ignition is measured by the [[octane rating]] of the fuel, where [[2,2,4-Trimethylpentane|2,2,4-trimethylpentane]] (''isooctane'') has an arbitrary value of 100, and [[heptane]] has a value of zero. Apart from their use as fuels, the middle alkanes are also good [[solvent]]s for nonpolar substances. Alkanes from [[nonane]] to, for instance, [[hexadecane]] (an alkane with sixteen carbon atoms) are liquids of higher [[viscosity]], less and less suitable for use in gasoline. They form instead the major part of [[Diesel fuel|diesel]] and [[aviation fuel]]. Diesel fuels are characterized by their [[cetane number]], cetane being an old name for hexadecane. However, the higher melting points of these alkanes can cause problems at low temperatures and in polar regions, where the fuel becomes too thick to flow correctly.