Electrochemical properties of uranium in lactones: Kinetics and electrodeposition

The electrochemical reductions of hexavalent and tetravalent uranium are reported in -butyrolactone, -valerolactone, -octanoiclactone and in the mixed solvent -butyrolactone/tetrahydrofuran. The transient techniques foresee either the formation of uranium dioxide or uranium metal according to a two-step reduction but the presence of these cathodic products is difficult to ascertain in controlled potential electrolysis. While mixing a lactone with tetrahydrofuran, the reversibility of the electrode reactions increases. The conducting salt noticeably determines the current yield of uranium deposition. As additional kinetic phenomena are made clear, we found that sampled polarography is the best method to gain a full understanding of the electrode mechanisms.