Kinetics of the Permanganate-Iron(II) Reaction in Aqueous Acid Medium

Article abstract of DOI:10.1021/j150648a032

The kinetics of the permanganate-iron(II) redox reaction has been studied in aqueous perchloric acid at 20 deg C by using stopped-flow techniques.The disappearance of permanganate was followed at 525 nm, with use of excess iron, and consisted of two consecutive first-order decays.A mechanism consistent with the data is MnO4^- + Fe²⁺ <*> O3MnOFe⁺ (k₁, k_-1), O3MnFe⁺ -> Mn(VI) + Fe(III) (k₂).The rate constants are k₁ = 9.97E4 M^-1 s^-1, k_-1 = 16.4 s^-1, and k₂ = 12.9 s^-1.No dependence on H⁺ or salt was observed in either step.