Isocetane (2,2,4,4,6,8,8-heptamethylnonane) is a highly branched
alkane
In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whi ...
used as a reference in determining the
cetane number
Cetane number (cetane rating) (CN) is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It plays a similar role for diesel as octane rating does for gasoline. The CN is an important factor in determining t ...
of diesel. It has a cetane number of 15.
Isocetane replaced
1-methylnaphthalene
1-Methylnaphthalene is an organic compound with the formula C11H10. It is a colorless liquid. It is isomeric with 2-methylnaphthalene.
Reference fuel
1-Methylnaphthalene defines the lower (zero) reference point of cetane number, a measure of di ...
in 1962 as the lower reference for cetane number (1-methylnaphthalene has cetane number zero) owing to the oxidation instability and difficulty of use of 1-methylnaphthalene in the reference engine.
Strictly speaking, if the standard meaning of ‘iso’ is followed, the name ''isocetane'' should be reserved for the isomer
2-methylpentadecane. However, 2,2,4,4,6,8,8-heptamethylnonane is by far the most important isomer of
cetane
Hexadecane (also called cetane) is an alkane hydrocarbon with the chemical formula C16H34. Hexadecane consists of a chain of 16 carbon atoms, with three hydrogen atoms bonded to the two end carbon atoms, and two hydrogens bonded to each of the 1 ...
and so, historically, it has ended up with this name.
References
Alkanes
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