KINETICS OF THE OXIDATION OF URANIUM(IV) BY MOLECULAR OXYGEN IN AQUEOUS PERCHLORIC ACID SOLUTION

The kinetics of the oxidation of uranium(IV) by molecular oxygen in aqueous perchloric acid solution were studied. Over a considerable range of conditions, the results are fitted approximately by the rate law:−d[UIV]/dt = k[UIV] [O2]/[H+], where k ≈ 2 × 1014 exp[−22,000/RT]sec.−1. The reaction is catalyzed by Cu++ and inhibited by small amounts of Ag+ and Cl−. The results are interpreted in terms of a chain reaction mechanism involving UO2+ and HO2 as chain carriers.