Abstract
Synergistic effect was observed in the extraction of trivalent lanthanides by the mixed solvent of TBPO (tri-n-butyl phosphine oxide) and TOPO (tri-n-octyl phosphine oxide) in toluene diluent. The reason of the enhancement was verified as mainly due to the formation of new extractable species $M(NO_3)_3(TBPO)_2\;(TOPO)$ besides of the formation of $M(NO_3)_3(TBPO)_3$and $M(NO_3)_3(TOPO)_3$.
TBPO와 TOPO와의 混合溶媒(稀釋制 : toluene)에 依한 三假狀態의 4f 稀土類元素의 抽出에 있어 相乘效果(synerigistic effect)가 나타남을 알았으며 이것은 各 單獨溶媒系에 있어서 生成抽出되는 $M(NO_3)_3\;(TBPO)_3$ 및 $M(NO_3)_3\;(TOPO)_3$型 外에 $M(NO_3)_3\;(TBPO)_2\;(TOPO)$型이 새로히 追加生成됨을 起因된 것으로 認定된다.