Effect of the Structure of Amido-polynitrogen Molecules on the Complexation of Actinides

AbstractThe complexation and solvent extraction of Eu(III) and actinides in different oxidation states (Am(III), Pu(IV), Np(V)) by bitopic molecules with a dipyridyl-phenanthroline cycle as nitrogen unit and one or two amido functions are described. The complexation has been studied in methanol-water solution with hydrophilic molecules to enhance knowledge about this new family of ligands and to identify the most interesting structural effect. Some extraction tests have been performed with lipophilic molecules of the family to check the possible utility of the new class of ligands under representative fuel reprocessing conditions. These first studies have demonstrated that the presence of a preorganized N-donors unit like dipyridyl-phenanthroline improves the ligand's affinity for actinides and its An/Ln selectivity

Une nouvelle forme symptomatologique du court noué de la vigne ? Qui a vu celà ?

National audienc

Extraction of RF equivalent circuit and semiconductor parameters of SOS MOSFETs from S-Parameter measurements

This paper describes the use of on-wafer measured microwave scattering parameters (S-parameters) for the extraction of RF equivalent circuit elements and semiconductor parameters of an SOS MOSFET. © Copyright 2011 IEEE – All Rights Reserve

Importance of thermochemistry in the development of actinides extraction processes

International audienc

Speciation and Thermodynamics Data to better describe the Efficiency of Actinides Separation by N,N-dialkylamides

International audienc

Radiolytic stability of N , N -dialkyl amide: effect on Pu( iv ) complexes in solution

International audienc

Investigation under ionizing radiation of Pu(IV) - monoamide complexes in solution

International audienceIn 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)

Perrhenate and pertechnetate complexation by an azacryptand in nitric acid medium

Technetium is present as the pertechnetate anion in spent nuclear fuel solutions, and its extraction by several extractant systems is a major problem for the liquid-liquid extraction processes used to separate uranium and plutonium. To prevent technetium extraction into the organic phase, a complexing agent may be added to the aqueous nitric acid phase to selectively bind the pertechnetate anion. In the present study, liquid-liquid extraction experiments reveal that technetium distribution ratios are considerably lowered with addition of an azacryptand, which is a good receptor for pertechnetate anion recognition. This ligand is able to overcome the Hofmeister bias and selectively bind techetium in nitric acid solution. Coordination studies using infrared and Raman spectoscopies and DFT calculations show the formation of an inclusion complex with hydrogen bonds stabilizing the oxo-anion within the cavity. For the first time, the cage molecules are studied for an extraction process