Abstract
Solvent extraction of europium(III) and thulium(III) has been investigated by high molecular weight β-diketone derivatives, such as dodecylbenzoyltrifluoroacetone (LIX51), benzoylisooctanoylmethane (LIX54) and dibenzoylmethane (DBM), in the presence of neutral donors, such as tributyl phosphate (TBP) and trioctylphosphine oxide (TOPO). The distribution ratio was largely enhanced by a synergistic effect. Tris-β-diketonates forms mono- and di-adducts with TBP and TOPO depending on the kind of β-diketones and central metals. The extraction constants with β-diketones alone were of the order LIX 51_??_LIX 54>DBM, whereas the adduct formation constants followed the order LIX 51>DBM>LIX 54. The separation factor between thulium and europium decreased in the presence of neutral ligands.
