Investigation under ionizing radiation of An-ligand complexes in solution by electrospray ionization mass spectrometry
Résumé
In nuclear fuel reprocessing, the organic ligands in solution are subjected to radiolysis. The resulting effects can lead to modifications of the solution composition which can alter the extraction properties of the ligands, specifically, their extraction efficiency and selectivity. Therefore, it is important to study the effect of radiolysis on the ligands in the organic phase to identify weak points in their molecular structure. This identification can facilitate the design of more stable ligands and of ligands that generate innocuous degradation products. The aim of this work is to increase the understanding of ligand behavior when exposed to ionizing radiation. Specifically, this work aims to characterize the degradation products formed as a result of radiolysis of monoamide extractants involved in plutonium complexes by electrospray ionization mass spectrometry (ESI-MS). ESI-MS is a powerful technique that can be used to identify products through both charge and mass characterization which is especially useful when trying to determine complex formation between degradation products and metal ions. In addition to in-situ alpha irradiation, non-complexed extractants have been irradiated by a gamma source allowing direct comparisons to be made between the type of irradiation and the resulting degradation products that form. To investigate the effect of the structure on the stability of the ligand, in particular the effect of the alkyl group on the carbonyl function, three extractants were chosen, N, N-di-(2-ethylhexyl)butryamide (DEHBA), N, N-di-(2-ethyhexyl)isobutyramide (DEHiBA), and N, N-di-(2-ethylhexyl)-3, 3-methylbutyramide (DEHDMBA).