Reaction of OH with aromatic molecules

A simple explanation [36] for these observations is that formation of the [HOCeHsX] radical proceeds via an intermediate that can dissociate back to the reactants in competition with the forward step. It has been proposed [36] that the intermediate is a r-complex in which the electrophyUc OH interacts with the r-electrons of the aromatic ring as a precursor of the cr-bonded [HOCeHsX] radical. Such a mechanism has also been considered by others [37-39], 

substitution of Kbs in equation (8) results in the parameters listed in Table 3. These show that rearrangement of the r-radicals to the oradicals requires little or no activation energy, whereas dissociation of the r-radicals has an activation energy of ca. 20 kJ mol.  

Finally, the differences in the absolute values of k s are largely reflected in the values of k2o, suggesting that the electronic effects of the substituents X govern the rearrangement reaction (20). 

The original impetus to measure rate constants in vs ter at elevated temperatures provided by the development of nuclear power reactors but, as in many other innovations, there is a spin-off of value to wider fields of research. 

Progress in Reaction Kinetics, G. Porter (ed.), Pergamon Press, London, 1961, p. 129. 

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