Alkanes from
nonane to
hexadecane (those alkanes with nine to sixteen carbon atoms) are liquids of higher
viscosity, which are less suitable for use in
gasoline. They form instead the major part of
diesel,
kerosene, and
aviation fuel. Diesel fuels are characterised by their
cetane number, cetane being an older 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. Mixtures of the normal alkanes are used as
boiling point standards for simulated
distillation by
gas chromatography. Alkanes from hexadecane upwards form the most important components of
fuel oil and
lubricating oil. In latter function they work at the same time as anti-corrosive agents, as their
hydrophobic nature means that water cannot reach the metal surface. Many solid alkanes find use as
paraffin wax, used for
lubrication,
electrical insulation, and
candles. Paraffin wax should not be confused with
beeswax, which consists primarily of
esters. Alkanes with a chain length of approximately 30 or more carbon atoms are found in
bitumen (asphalt), used (for example) in road surfacing. However, the higher alkanes have little value and are usually split into lower alkanes by
cracking. == Names ==