A generalized form of the extraction constant for the partition of a metal chelate between immiscible aqueous and organic phases

Abstract

The theory underlying the partition of sparingly soluble reagents and their formally neutral metal chelates between an aqueous phase and any immisicible organic phase leads to a generalized extraction constant K * ex= K ex S n r,0/ S c,o where K ex is the conventional extraction constant and S r,o S c,o are the molar solubilities of reagent and metal complex, respectively, in the same organic solvent. The predicted constancy of K * ex is confirmed for measurements in seven solvents and for systems involving mono-, di- and tridithizonates of Ag +, Zn 2+ and Bi 3+, respectively.