Complexation of actinides and lanthanides with water-soluble amides and carboxylic acids and their tetrad effect

Sasaki, Yuji  ; Kaneko, Masashi   ; Ban, Yasutoshi  ; Nomizu, Daiki*; Tsuchida, Yusuke*; Matsumiya, Masahiko*; Nakase, Masahiko*; Takeshita, Kenji*; Shimosaka, Takahiro*; Suzuki, Tatsuya*

In order to enlarge the separation factors between trivalent actinide (An) and lanthanide (Ln), which show similar chemical behavior, the use of water-soluble ligand has been studied. In this work, ten of amides and carboxylic acids are employed in TODGA extraction system and their properties are compared. It is noted that complexing ability of amide with Ln is higher than that with carboxylic acid under pH 2, if both reagents have the same central frame. Classifying 14 lanthanides into four groups (La-Nd, Sm-Gd, Gd-Ho, and Er-Lu), the difference of their complexing reactions in each group and the reaction of An will be discussed.