Editing Alkane (section)

=== Free radical reactions ===
[[Free radical]]s, molecules with unpaired electrons, play a large role in most reactions of alkanes.  [[Free radical halogenation]] reactions occur with halogens, leading to the production of [[haloalkanes]]. The hydrogen atoms of the alkane are progressively replaced by halogen atoms.  The reaction of alkanes and fluorine is highly [[exothermic reaction|exothermic]] and can lead to an explosion.<ref>{{Ullmann |doi=10.1002/14356007.a11_349 |chapter=Fluorine Compounds, Organic  |last1=Siegemund |first1=Günter |last2=Schwertfeger |first2=Werner |last3=Feiring |first3=Andrew |last4=Smart |first4=Bruce |last5=Behr |first5=Fred |last6=Vogel |first6=Herward |last7=McKusick |first7=Blaine  }}</ref> These reactions are an important industrial route to halogenated hydrocarbons. There are three steps:
* '''Initiation''' the halogen radicals form by [[homolysis (chemistry)|homolysis]]. Usually, energy in the form of heat or light is required.
* '''Chain reaction''' or '''Propagation''' then takes place—the halogen radical abstracts a hydrogen from the alkane to give an alkyl radical. This reacts further.
* '''Chain termination''' where the radicals recombine.
Experiments have shown that all halogenation produces a mixture of all possible isomers, indicating that all hydrogen atoms are susceptible to reaction. The mixture produced, however, is not statistical: Secondary and tertiary hydrogen atoms are preferentially replaced due to the greater stability of secondary and tertiary free-radicals. An example can be seen in the monobromination of propane:<ref name = m&b/>
[[Image:Monobromination of propane.png|500px|center|Monobromination of [[propane]]]]

In the [[Reed reaction]], [[sulfur dioxide]] and [[chlorine]] convert hydrocarbons to [[Sulfonic acid|sulfonyl chlorides]] under the influence of [[photochemistry|light]].

Under some conditions, alkanes will undergo [[Nitration]].