Structural influences on the lanthanide-actinide selectivity of some aminocarboxylates

Data for the resolution of americium from europium and terbium using 2,2'-diaminodiethylether-N,N,N',N'-tetraacetate and 1,5-diaminopentane-N,N,N',N'-tetraacetate are reported along with values of the formation constants of the La-Lu and Y chelates of the latter. It is shown that the minimum single-stage separation factor for Am3+ from Ln3+ cations, using 2,2'-diaminodiethylether-N,N,N',N'-tetraacetate with Dowex 50 resin exceeds 1.7 for all Am-Ln pairs, and runs as high as 350 in the case of Am3+, La3+. The minimum of 1.7 occurs at Eu3+ in the lanthanon sequence. A novel separation of Am3+, Cm3+ and heavier actinons from each other and from all the lanthanons and yttrium appears to be feasible. (author)