The kinetics of the reaction between copper(II) and some ortho-hydroxyoximes

The kinetics of the reaction between copper(II) and salicylaldoxime were studied in various ethanol-water mixtures. The rate of reaction was found to be first order in both copper(II) and the neutral ligand. Deviations from this behaviour at low pH can be accounted for if allowance is made for the reverse reaction and for protonation of the ligand. A mechanism that involves the rate-determining formation of the mono-complex has been found to describe the kinetic data with the rate constant in 80 per cent ethanol being 3.7 × 10⁴ mol^?4 ls^?1 at 11°C. The kinetic data have been used in a preliminary assessment of the location of the reaction in the extraction of copper(II) by hydroxime solvents.