Octane is the primary component of fuel, composing over 90% of the
fuel in some cases. There is a very good description of this process at
http://www.r-t-o-l.com/laboratory/learning/faq1.htm#q3
; however, the description there contains a lot of extraneous information
that is not used here, so the information from that site was summarized and
combined with information from several other sites to form the following paragraph:
During the burning process of hydrocarbons (chemicals made up of
only hydrogen and carbon, such as octane), hydrogen atoms are removed from
the hydrocarbon by OH- and HO2- ions, as
well as free-floating oxygen (O2-) and hydrogen (H-
) atoms. These free-floating atoms and molecules exist at the source of
the flame, so burning cannot start in this manner before the flame has reached
any given area. However, heat can also cause these molecules to spontaneously
ignite before the flame reaches them. Long, straight hydrocarbons like n-Octane
(and n-Heptane, similar to n-Octane except with one less CH2 group;
this chemical is used in gasoline, as will be described in detail later on)
are more susceptable to spontaneous combustion than branched hydrocarbons
such as iso-octane, because the hydrogen bonds in branched hydrocarbons are
stronger and more resistant to heat.
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