A method for the determination of extraction capacity and its application to -tetraalkylderivatives of diglycolamide-monoamide/n-dodecane media

抽出容量測定の新手法とそのDGA-モノアミド/n-ドデカン中のNd(III)測定への応用

佐々木 祐二  ; 須郷 由美; 鈴木 伸一; 木村 貴海 

Sasaki, Yuji; Sugo, Yumi; Suzuki, Shinichi; Kimura, Takaumi

新しい抽出容量の測定方法を用いて、DGA-DHOA/n-ドデカン抽出溶媒中のNd(III)の抽出容量(LOC)を測定した。LOC値は硝酸濃度や温度に依存することがわかった。LOCの値は十分な濃度のモノアミド(DHOA)を加えた系で化学量論値に達し、またこの系では第三相は生成しなかった。DHOAを含まない系で、異なる構造のDGA化合物を用いてLOCを測定したところ、アルキル鎖の長い官能基(テトラドデシル基)を導入したTDdDGA化合物を用いると、第三相は生成せず、LOC値も化学量論値に到達した。本研究により、DHOAを加えることと長いアルキル鎖を導入したDGA化合物を用いることが、第三相を抑制し、抽出容量を増大させることに重要であることがわかった。

The detailed study of extraction capacity of diglycolamide (DGA) with and without DHOA, N,N'-dihexyloctanamide as a modifier, was performed by using the novel analytical method for the determination of the limit of metal concentration in the organic phase (LOC). The effect on modifier was studied and it is confirmed that LOC increases with DHOA concentration. It is noteworthy that LOC reaches to the stoichiometric value, which is obtained by the extraction reaction, by using 0.1M TODGA mixed with more than 0.5M DHOA into n-dodecane. Without modifier, relation of the different DGA compounds with LOC was investigated, and it is clear that LOC using N,N,N',N'-tetradodecyl-diglycolamide (TDdDGA), whose extractant can suppress the third phase, reaches to the stoichiometric value. From this work, it is obvious that the application of the condition without the third phase formation, e.g., enough concentration of modifier coexisted and DGA with long alkyl chain, is important to attain the stochiometric LOC value.