Reactions between haemin and hydrogen peroxide. Part 3.—Catalytic decomposition of hydrogen peroxide

Abstract

This paper reports kinetic studies of the catalysis with haemin (A) at 0°C, in the pH range 6.5–13.2, with initial hydrogen peroxide concentrations between 1 × 10^–3 and 5 × 10^–1 M. The reaction rate increases with increasing pH in a manner which is not accounted for by previous theories of the reaction. It is suggested that haemin (A) and haematin (A) act as independent catalytic entities. Results at high concentrations of hydrogen peroxide, after correction for catalyst oxidation, show no evidence for the di-peroxy haemin complex which has been reported to be formed in pyridine solution.