Kinetics and mechanism of the oxidation of catechol by Fe2(bipy)4O4+ in aqueous hydrochloric acid medium

Abstract

The kinetics of the oxidation of catechol, an orthodihydroxybenzene by Fe2(bipy)4O4+ (bipy = 2,2¹-bipyridine) has been studied in aqueous hydrochloric acid medium. In the acid range [H⁺] = 1 x 10^-5 -
12 x 10^-5 mol dm^-3. The kinetic data are consistent with the rate law:
 Rate = k_obs[Fe₂O₄⁺]  where k_obs = 0.022  0.002 s-1 at 290C and 0.01 mol dm^-3 ionic strength. The reaction rate was not affected by change in the dielectric constant of the reaction medium and added anions. An outersphere via ion pair pathway is proposed for the reaction.