Synthesis and characterization of bis-succinamides for extraction of UO2 2+ from nitric acid solution

Several novel extractants based on the bis-succinamide (BisSCA) structure have been synthesized and characterized by NMR, IR and HRMS. Extraction distribution ratios of U(VI) have been studied as a function of popular diluents and aqueous concentrations of HNO3 as well as extractant concentration. In contrast with single succinamide extractants, the BisSCA extractants exhibited better extraction efficiency in the present system, and suggesting that BisSCAs could efficiently associate with uranyl ion in different mode of complexation. Based on the relationships between logD U(VI) and log[BisSCA] under different ionic strengths, the preferable compositions of extracted species were presumed to be the major [UO2(NO3)2]2·[BisSCA]2 and the minor UO2(NO3)2·[BisSCA]2.