Editing Halogenation (section)

===Free radical halogenation ===
{{Main|Free-radical halogenation}}
Halogenation of [[saturated hydrocarbon]]s is a [[substitution reaction]]. The reaction typically involves [[free radical]] pathways. The [[regiochemistry]] of the halogenation of [[alkanes]] is largely determined by the relative weakness of the [[Carbon–hydrogen bond|C–H bonds]]. This trend is reflected by the faster reaction at [[Tertiary (chemistry)|tertiary]] and [[Secondary (chemistry)|secondary]] positions. 

Free radical chlorination is used for the industrial production of some [[solvents]]:<ref name=Ullmann>{{Ullmann|doi=10.1002/14356007.a06_233.pub2}}</ref>
:{{chem2|CH4 + Cl2 → CH3Cl + HCl}}

Naturally-occurring [[organobromine compound]]s are usually produced by free radical pathway [[catalyzed]] by the [[enzyme]] [[bromoperoxidase]]. The reaction requires [[bromide]] in combination with [[oxygen]] as an [[oxidant]]. The [[oceans]] are estimated to release 1–2 [[million]] tons of [[bromoform]] and 56,000 tons{{which|reason=Short ton, long ton or metric ton?|date=July 2023}} of [[bromomethane]] annually.<ref>{{cite journal|doi=10.1039/a900201d|title=The diversity of naturally occurring organobromine compounds|year=1999|last1=Gribble|first1=Gordon W.|journal=Chemical Society Reviews|volume=28|issue=5|pages=335–346}}</ref>

The [[iodoform reaction]], which involves degradation of [[methyl ketone]]s, proceeds by the free radical iodination.