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4 results on '"O. Pecheur"'

1. Synergism in a HDEHP/TOPO Liquid−Liquid Extraction System: An Intrinsic Ligands Property?

Author

Sandrine Dourdain, J. Rey, Stéphane Pellet-Rostaing, Marie-Christine Charbonnel, O. Pecheur, Philippe Guilbaud, Dominique Guillaumont, Fabienne Testard, Laurence Berthon, Département RadioChimie et Procédés (DRCP), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
inorganic chemicals, Chemistry, Vapor pressure osmometry, Supramolecular chemistry, Infrared spectroscopy, Nanotechnology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Mass spectrometry, 01 natural sciences, Micelle, 0104 chemical sciences, Surfaces, Coatings and Films, Molecular dynamics, Liquid–liquid extraction, Materials Chemistry, Molecule, Physical chemistry, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract

International audience; Among the proposed mechanisms to predict and understand synergism in solvent extraction, the possibility of a preorganization of the mixture of extractant molecules has never been considered. Whether involving synergistic aggregation as for solubilization enhancement with reverse micelles or favored molecular interaction between the extractant molecules, evaluation of this hypothesis requires characterization of the aggregates formed by the extractant molecules at different scales. We investigate here the HDEHP/ TOPO couple of extractant with methods ranging from vibrational spectroscopy and ESI-MS spectrometry to vapor pressure osmometry and neutron and X-ray scattering to cover both molecular and supramolecular scales. These experimental methods are subjected to DFT calculations and molecular dynamics calculations, allowing a rationalization of the results through the different scales. Performed in the absence of any cation, this original study allows a decorrelation of the mechanisms at the origin of synergy: it appears that no clear preorganization of the extractants can explain the synergy and therefore that the synergistic aggregation observed in the presence of cations is rather due to the chelation mechanisms than to intrinsic properties of the extractant molecules.

Published
2016
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2. Synergism by Coassembly at the Origin of Ion Selectivity in Liquid–Liquid Extraction

Author

Thomas Zemb, Sandrine Dourdain, Jacques Jestin, Jean-François Dufrêche, Antoine Leydier, O. Pecheur, Raphaël Turgis, I. Hofmeister, Stéphane Pellet-Rostaing, Fabienne Testard, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation Mésoscopique et Chimie Théorique (LMCT), Laboratoire d'Ingénierie des Matériaux de Bretagne (LIMATB), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Bretagne Sud (UBS)-Institut Brestois du Numérique et des Mathématiques (IBNM), and Université de Brest (UBO)-Université de Brest (UBO)-Université de Brest (UBO)

Subjects
Chemistry, Dodecane, Small-angle X-ray scattering, 02 engineering and technology, Surfaces and Interfaces, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Ion, Solvent, chemistry.chemical_compound, Chemical engineering, Liquid–liquid extraction, Phase (matter), Electrochemistry, Organic chemistry, [CHIM]Chemical Sciences, General Materials Science, 0210 nano-technology, Selectivity, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Phase diagram
Abstract

In liquid-liquid extraction, synergism emerges when for a defined formulation of the solvent phase, there is an increase of distribution coefficients for some cations in a mixture. To characterize the synergistic mechanisms, we determine the free energy of mixed coassembly in aggregates. Aggregation in any point of a phase diagram can be followed not only structurally by SANS, SAXS, and SLS, but also thermodynamically by determining the concentration of monomers coexisting with reverse aggregates. Using the industrially used couple HDEHP/TOPO forming mixed reverse aggregates, and the representative couple U/Fe, we show that there is no peculiarity in the aggregates microstructure at the maximum of synergism. Nevertheless, the free energy of aggregation necessary to form mixed aggregates containing extracted ions in their polar core is comparable to the transfer free energy difference between target and nontarget ions, as deduced from the synergistic selectivity peak.

Published
2012
Full Text
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3. Synergism in a HDEHP/TOPO Liquid-Liquid Extraction System: An Intrinsic Ligands Property?

Author

Pecheur O, Dourdain S, Guillaumont D, Rey J, Guilbaud P, Berthon L, Charbonnel MC, Pellet-Rostaing S, and Testard F

Abstract

Among the proposed mechanisms to predict and understand synergism in solvent extraction, the possibility of a preorganization of the mixture of extractant molecules has never been considered. Whether involving synergistic aggregation as for solubilization enhancement with reverse micelles or favored molecular interaction between the extractant molecules, evaluation of this hypothesis requires characterization of the aggregates formed by the extractant molecules at different scales. We investigate here the HDEHP/TOPO couple of extractant with methods ranging from vibrational spectroscopy and ESI-MS spectrometry to vapor pressure osmometry and neutron and X-ray scattering to cover both molecular and supramolecular scales. These experimental methods are subjected to DFT calculations and molecular dynamics calculations, allowing a rationalization of the results through the different scales. Performed in the absence of any cation, this original study allows a decorrelation of the mechanisms at the origin of synergy: it appears that no clear preorganization of the extractants can explain the synergy and therefore that the synergistic aggregation observed in the presence of cations is rather due to the chelation mechanisms than to intrinsic properties of the extractant molecules.

Published
2016
Full Text
View/download PDF

4. Synergism by coassembly at the origin of ion selectivity in liquid-liquid extraction.

Author

Dourdain S, Hofmeister I, Pecheur O, Dufrêche JF, Turgis R, Leydier A, Jestin J, Testard F, Pellet-Rostaing S, and Zemb T

Abstract

In liquid-liquid extraction, synergism emerges when for a defined formulation of the solvent phase, there is an increase of distribution coefficients for some cations in a mixture. To characterize the synergistic mechanisms, we determine the free energy of mixed coassembly in aggregates. Aggregation in any point of a phase diagram can be followed not only structurally by SANS, SAXS, and SLS, but also thermodynamically by determining the concentration of monomers coexisting with reverse aggregates. Using the industrially used couple HDEHP/TOPO forming mixed reverse aggregates, and the representative couple U/Fe, we show that there is no peculiarity in the aggregates microstructure at the maximum of synergism. Nevertheless, the free energy of aggregation necessary to form mixed aggregates containing extracted ions in their polar core is comparable to the transfer free energy difference between target and nontarget ions, as deduced from the synergistic selectivity peak.

Published
2012
Full Text
View/download PDF

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