UO₂²⁺ extraction and mechanism by diglycolamide extractants with different ether-oxygen chain skeletons

The study of the structure and properties of extractants is of great significance for developing new extractants. For uranium extraction and recovery requirements in spent fuel reprocessing, three kinds of extractants with different ether-oxygen chains, N,N,N’N’-tetraoctyl-3-oxapentanediamide (TODGA), N,N,N’N’-tetraoctyl-3,6-dioxaoctanediamide (TODOODA) and N,N,N’N’-tetraoctyl-3,6,9-trioxaundecanediamide (TOUDA) were synthesized to study the influence of the ether-oxygen chain skeleton on the extraction of uranium from nitrate media. TODOODA shows a good extraction ability for uranyl ions at high nitric acid concentrations. Equimolar series method, FT–IR spectrum and MALDI–TOF–MS spectra indicated that the extracted structure was formed as [UO₂NO₃·TODGA]NO₃, [UO₂NO₃·TODOODA]NO₃ and [UO₂NO₃·TOUDA]NO₃.