Cyclohexadienyl radicals aromatic compounds

The formation of hydroxymethyl cyclohexadienyl peroxy radical (E) by pathway (c) in Reaction Scheme 7.10 is thought to be the most important as a process to produce ring-opened compounds, which are well known reaction products of OH and aromatic hydrocarbons. The O2 addition reaction to the OH-added benzene ring radical is reversible, and in the case of benzene, the equilibrium constant and the enthalpy change is given as K(298 K) = (8.0 0.6) x 10 ° cm molecule" (Johnson et al. 2002), and = ( 44 2) kJ mol (Grebenkin and Krasnoperov 2004) for the hydroxycyclohexadienyl radical. Therefore, hydroxycyclohexadienyl radicals formed in pathway (c) are in general stable in the atmosphere, and play an important role as intermediates in the oxidation reactiOTi of aromatic compounds. 

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