Chelate complex is formed by a reaction of a divalent metal and chelating reagents. This reaction can be applied to the extraction of copper.
When the divalent cupric ion in the aqueous phase is extracted by the chelating reagent in the immiscible organic phase, the chemical reaction may take place at the liquid-liquid interface.
There are two reaction mechanisms in the following cases; one is the rate-determining step being in the formation of monovalent complex composed of one cupric ion and one extractant, and the other neutral complex composed of one cupric ion and two extractants.
The objectives of this study are analyzing correctly for the two cases and finding the rate-determining step through the experiments. Salicylaldoxime, a kind of hydroximes, was used for the extractant in a stirred transer cell. The rate-determining step was found to be the first step forming the monovalent complex and the extraction rate was proportional to the half and first order for the two reactants, the cupric ion and the extractant in the aqueous and the organic phases, respectively.
