Ammonium-Based Amide-Functionalized Task-Specific Ionic Liquid for Actinide Separations

A new ammonium-based task-specific ionic liquid, N,N-dioctyl-(4-trihexylammonium)butyramide bis(trifluoromethanesulfonyl)imide ([AmDOA][NTf2]), was synthesized and characterized by elemental analysis, and Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopies. The extraction behavior of Pu(IV), U(VI), and Am(III) from nitric acid medium was studied in a solution of [AmDOA][NTf2] in an ionic liquid diluent, methyltributylammonium bis(trifluoromethanesulfonyl)imide ([N-1444][NTf2]). The distribution ratio of actinides obtained in [AmDOA][NTf2]/[N-1444][NTf2] was compared with other task-specific ionic liquids. The extraction stoichiometry of Pu(IV) in ionic liquid phase was determined, and the conditions needed for the efficient recovery of Pu(IV) from the loaded organic phase were evaluated. The results of these studies are reported in this article.