Actinides extractability trends for multidentate diamides and phosphine oxides

多座配位性のジアミド,リン酸化物のアクチノイド抽出性能の序列

佐々木 祐二  ; 北辻 章浩  ; 須郷 由美; 津幡 靖宏   ; 木村 貴海 ; 森田 泰治  

Sasaki, Yuji; Kitatsuji, Yoshihiro; Sugo, Yumi; Tsubata, Yasuhiro; Kimura, Takaumi; Morita, Yasuji

多くの中心骨格を持つジアミド,リン酸化物抽出剤を用いてアクチノイドの溶媒抽出を行った。アクチノイドの溶媒抽出の結果から、6員環を形成し、2つのリン酸基を持つBDPPMが最も高い抽出性能を示した。一方、BDPPMはドデカンに溶解しない問題点を持つ。希釈剤への溶解性、合成の容易さ、使用後の燃焼処分の可能性、アクチノイドの抽出性能を考慮すると、ジグリコールアミド化合物が高レベル廃液からの抽出には有効であることが確認された。

Diamides and phosphine oxides having many kinds of the central frames were synthesized and employed in order to see the behavior of actinides(An)(III), (IV), (V) and (VI). Diamides synthesized here have two, three, or four donor atoms of amidic and etheric oxygen (nitrogen or sulfur, instead) atoms in their central frames, namely the extractants can work as bi-, tri-, and tetradentate modes. Di-phosphine di-oxides ((Bis(diphenylphosphoryl)methane (BDPPM) and bis(diphenylphosphoryl)ethylene (BDPPE)), carbamoylmethylphosphine oxide (octylphenyl-,-diisobutyl-carbamoylmethylphosphine oxide (CMPO)) are used as the representative actinide extractants. Metal ions of Eu(III), Th(IV), U(VI), Np(V), Pu(IV) and Am(III) in perchloric acid were extracted into nitrobenzene or n-dodecane. Measurement of value at the different extractant concentration gives the information on extraction reaction and their extraction ability. From the present work, the best extractant is BDPPM, due to the strong affinity concerning P=O and form of the bidentate mode with six-membered ring chelation. However, this extractant have low solubility in -dodecane. Taking the applicatory properties, e.g., high solubility in -dodecane, easy organic synthesis, gasification by combustion and high actinide extractability, into consideration, diglycolamide (DGA) is a promising extractant for radioactive waste treatment.