A KINETIC-STUDY OF COPPER-ION EXTRACTION BY KELEX-100 AT A HEPTANE-WATER INTERFACE

A study of the kinetics of Cu2+ extraction by 7-(4-ethyl-1-methyloctyl )8-hydroxyquinoline (Kelex 100) has been undertaken in a static transf er cell, where the total concentration of the Cu2+ - Kelex 100 complex In the organic phase is monitored in situ as the reaction proceeds us ing attenuated total internal reflectance spectroscopy. The temporal c haracteristics of the extraction of Cu2+ from water into heptane could be accounted for using a simple one-dimensional diffusion model coupl ed with a reaction-limited interaction between Cu2+ and Kelex 200. Rat e constants for the reaction of Kelex 100 and Cu2+ at a model interfac e were obtained from stopped flow experiments using a neutral micelle (C(12)E(8)) system. These rate constants were used to model the reacti on between Cu2+ and Kelex 100 at the heptane-water interface. (C) 1996 Academic Press, Inc.