抄録
The synergistic extraction of rare earth elements has been investigated by a mixture of a high molecular weight β-diketone, dibenzoylmethane (Hdbm, HA), and a new neutral ligand (S), 3, 5-di (2-pyridyl) pyrazole (dpp), as well as a typical neutral bidentate ligand, 2, 2'-bi-4-picoline (bp). Large synergistic enhancement was produced owing to the formation of the adduct complexes such as MA_3S in both neutral ligand -systems. Extraction constants with Hdbm alone and those in the presence of the neutral ligand were evaluated for rare earth elements, and the adduct formation constants for dpp was found to be close to those for bp. The separation factors for lighter rare earth elements were also enhanced through the synergistic effect with dpp and bp.
