Voltammetric study of copper(II) dialkyldithiophosphates formed by the interaction of dialkyldithiophosphates with copper salts

Abstract

The in situ formation in organic media of copper(II)O,O′-dialkylphosphorodithioates [dialkyldithiophosphates (DDPs), where alkyl = 2-methylethyl (isobutyl) or 1-methylethyl (isopropyl)] can be detected voltammetrically at the mercury electrode. The results show that the electrode reactions involve irreversible, diffusion-controlled processes with adsorption phenomena featuring significantly in studies involving DDP (alkyl = isopropyl) species. From a quantitative analytical perspective, the measurement of the Cu^II reduction peak height may prove useful for the determination of CuDDP complexes. Voltammetric wave assignments and a scheme for the processes occurring are presented. Finally, the log(stability constant) of copper(II)-DDP (alkyl = isobutyl) is calculated to be 17.3.