title: Stability of reverse micelles in rare-earth separation: a chemical model based on a molecular approach.
abstract: Molecular complexes formed in the organic phase during solvent extraction may self-assemble as reverse micelles, and therefore induce a supramolecular organization of this phase. In most of the cases, water molecules play an essential role in the organization of this non polar medium. The aim of this work is to investigate the speciation of the aggregates formed in the organic phase during solvent extraction, and especially to assess their stability as a function of the number of water molecules included in their polar core. We have focused on malonamide extractants that have already been investigated experimentally. Different stoichiometries of reverse micelles in the organic phase have been studied by means of classical molecular dynamics simulations. Furthermore, umbrella-sampling molecular dynamics simulations have been used to calculate the equilibrium constant (K°) representing the association/dissociation pathways of water molecules in the aggregates and the corresponding reaction free energies (ΔrG°).
authors.affiliation: Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France. magali.duvail@icsm.fr.
authors.forename: Yushu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France. magali.duvail@icsm.fr.
authors.forename: Magali
authors.identifier: http://orcid.org/0000-0003-1586-260X
authors.initials: M
authors.lastname: Duvail
authors.affiliation: CEA Marcoule, Nuclear Energy Division, RadioChemistry & Processes Department (DRCP), Site de Marcoule, F-30207 Bagnols-sur-Cèze Cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Guilbaud
authors.affiliation: Institut de Chimie Séparative de Marcoule (ICSM), UMR 5257, CEA-CNRS-Université Montpellier-ENSCM, Site de Marcoule, Bâtiment 426, BP 17171, F-30207 Bagnols-sur-Cèze Cedex, France. magali.duvail@icsm.fr.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Dufrêche