# Reed reaction

The Reed reaction is a chemical reaction that utilizes light to oxidize hydrocarbons to sulfonyl chlorides. The reaction performs via the free radicals. First, the light makes a molecule of chlorine dissociate homolytically, then a chlorine atom produced attacks the hydrocarbon chain to form hydrogen chloride what results in the formation of alkyl free radical. Then SO2 as an electron donor bonds to the reaction center, forming an sulfonyl radical. Finally, the least one attacks another chlorine molecule to produce a sulfonyl chloride and a new chlorine atom which continues the reaction chain.

Chain initiation:

${\displaystyle {\ce {Cl2->[h\nu ]2Cl.}}}$

Chain propagation steps:

${\displaystyle {\ce {{R-H}+.Cl->{R.}+HCl}}}$
${\displaystyle {\ce {{R.}+{:}SO2->R-{\dot {S}}O2}}}$
${\displaystyle {\ce {{R-{\dot {S}}O2}+Cl2->{R-SO2-Cl}+Cl.}}}$

The resulting sulfonyl chlorides are widely used in the detergent industry as a raw material.

Under particular circumstances (40–80 °C) only chlorination of alkane may take place.

${\displaystyle {\ce {{R-H}+SO2Cl2->{R-Cl}+{SO2}+HCl}}}$

• Helberger, J. H.; Manecka, G.; Fischer, H. M. (1949). Ann. 562: 23. Missing or empty |title= (help)