Electroreduction of alkali metal cations. Part 1.—Effects of solution composition

Abstract

The kinetics of electroreduction of alkali metal cations have been determined at mercury in dimethylformamide and other organic solvents containing various tetra-alkylammonium perchlorates as supporting electrolytes. The kinetic parameters were observed to depend markedly on solution composition, the standard rate constant increasing with decrease in cation solvating ability of the solvent and with increase in crystallographic radius of the tetra-alkylammonium cation. On the basis of a detailed analysis of double layer effects for these systems, it is concluded that the rate determining step is transfer of the alkali metal cation from the solution phase to the mercury phase; the transfer of an electron to the metal ion in the double layer and subsequent incorporation of the metal atom in the mercury phase is not an important pathway for the process.