A kinetic method for measuring the relative rates of hydroxylation of naphthalene derivatives/cyclohexene has been developed. With this technique a linear relationship between the logarithm of the rates of oxidation products and the oxidation potentials of the naphthalene derivatives has been observed. Plots of sigma Hammett and sigma(+) Hammett-Brown with logarithm of relative rates have been linear and shown rho = -0.98 and rho(+) = -0.58, respectively. This contrast aromatic oxidation in protic solvents in which the oxidation products are naphthoquinones and provides further evidence for the intermediacy of carbocation in the hemin catalyzed hydroxylation of aromatic rings. (C) 2004 Elsevier B.V. All rights reserved.