Mixed-ligand chelate extraction of trivalent lanthanides and actinides with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 and dihexyl-n, n-diethylcarbamoylmethyl phosphonate

Mixed-ligand chelate extraction of trivalent lanthanides such as La, Eu and Lu and a trivalent actinide, Am into xylene with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP) and dihexyl-N, N-diathylcarbamoylmethylphosphonate (CMP) has been studied by tracer techniques. These trivalent metal ions are found to be extracted from 0.01 mol/dm3 chloroacetate buffer solutions as M(PMBP)3 x HPMBP type self adducts with HPMBP alone and in the presence of CMP as M(PMBP)3 x CMP (where M= La, Eu, Lu and Am) into the organic phase. The equilibrium constants of the above species are deduced by non-linear regression analysis. The synergistic constants of trivalent lanthanides do not increase monotonically with atomic number but have a maximum at Eu and that of Am was found to lie between that of La and Eu. (author). 12 refs., 3 figs., 3 tabs