Rate of equilibration in the two-phase system water+tri-n-butyl phosphate

Abstract

When water and tri-n-butyl phosphate (TBP) are equilibrated, the uptake of water by TBP results in an increase in volume of the organic phase. The rate of transference of water into TBP has been studied by measuring this volume increase as a function of time for a system in which the two phases are confined in a capillary tube to suppress convection effects. The results are interpreted in terms of two successive processes, interfacial transfer against an energy barrier, and the diffusion of water molecules through the bulk organic phase. The rate equations for these two processes are discussed with respect to the intermolecular interactions at the interface and in the organic phase.