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| Hauptseite > Publikationsdatenbank > Solvent extraction studies of different diastereomers of modified diglycolamide ligands for An(III) and Ln(III) extraction |
| Hauptseite > Publikationsdatenbank > Solvent extraction studies of different diastereomers of modified diglycolamide ligands for An(III) and Ln(III) extraction |
| Poster (Other) | FZJ-2022-03472 |
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2022
Abstract: Solvent extraction is currently the preferred technique for the separation of actinides (An) from fission products(FP), and especially lanthanides (Ln), as constituents of Spent Nuclear Fuel (SNF) or PUREX raffinate. A specialinterest is on the separation of Am from Cm, Ln and other FP by testing various ligands to upgrade the currentmethods. Diglycolamide (DGA) derivatives have shown promising results as extractants for trivalent Ln and An,such as, N,N,N’,N’-tetra-n-octyl diglycolamide (TODGA), which usually have a higher affinity for Cm(III) overAm(III). Wilden et al. [1] reported a change on Am(III) selectivity over Cm(III) with methyl substitutions withdifferent orientation in the backbone of Me2-TODGA. Here, we study the selectivity and affinity of relatedextractants (TODGA and N,N,N’,N’-tetra-n-decyl diglycolamide, TDDGA) with dipropyl and ethyl-methylsubstitutions in the molecule backbone, and their respective diastereomers (syn or anti) in n-dodecane. Thechemical structures are shown in Figure 1 An inverse selectivity is observed for Am(III) over Cm(III) and otherLn(III) at high nitric acid concentration (7 - 10 mol L-1 HNO3). The steric hindrance gives low distribution ratios(D < 1.5) for the trivalent metal ions at 0.1 mol L-1 ligand concentration, as shown in Figure 2. Besides trivalentions, Pu(IV) was also tested with the interest on the complexation behavior with tetravalent ions, which showsremarkably higher distribution ratios at the same HNO3 concentrations (D > 10). This is unlike methyl anddimethyl-TODGA, which present similar distribution ratios between trivalent and tetravalent metal ions. The synethyl-methyl substitutions for both analogues showed the highest D values for Am(III) among the tested ligands,giving a promising molecule for further studies. The results of the extraction studies will be presented anddiscussed in the poster.References1. Wilden, A., et al., Unprecedented Inversion of Selectivity and Extraordinary Difference in theComplexation of Trivalent f-Elements by Diastereomers of a Methylated Diglycolamide. Chem. Eur. J.,2019. 25(21): p. 5507-5513.
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