“…The extraction equilibrium based on these dependencies is shown in eq 1, and the relationship of the extraction equilibrium constant K ex to the distribution constant of the metal complex K DC , the distribution constant of the ligand K DR , the acid dissociation constant of the ligand K a , and the stability constant of the ML 3 complex β LL is given in eq 2
The averages of log K ex from batch and CPC experiments, and log β LL calculated from the K ex values, using the K DR , K DC , and K a values determined independently, are listed in Tables and , respectively, where it can be seen that these values increase with the atomic numbers of the lanthanides, similar to previous observations with other ligands. ,,− ,, It is also evident that the tervalent lanthanides have better extractabilities with HPMBP than with HPMCP, but the separation factors with the two ligands for a given pair of lanthanides, as indicated by the differences in their log K ex values, are about the same. The log β LL values, shown in Table , for the HPMCP complexes are 3 orders of magnitude larger than those for the HPMBP complexes, indicating that HPMCP forms much stronger complexes than does HPMBP.…”