New Mechanistic Aspects of the Fenton Reaction

Abstract The kinetics of the Fenton reaction was studied in detail. A second reaction step in the presence of excess H 2 O 2 is attributed to formation of the complex Fe III ( − O 2 H) aq . Therefore, the reaction of Fe(H 2 O) 6 2+ with Fe III ( − O 2 H) aq in the presence of Fe II to form Fe III aq ( k =(7.7±1.5)×10 5 M −1 s −1 ) may contribute to the overall Fenton reaction, and could account for some of the debate in the literature concerning its detailed mechanism. If this is correct for LFe III ( − O 2 H) aq also, then it might be of significant biological importance. The activation parameters Δ H ≠ , Δ S ≠ , and Δ V ≠ for the Fenton reaction were measured under various experimental conditions, and are used in the mechanistic interpretation.