title: Comparative Molecular Dynamics Study on Tri-n-butyl Phosphate in Organic and Aqueous Environments and Its Relevance to Nuclear Extraction Processes.
abstract: A refined model for tri-n-butyl phosphate (TBP), which uses a new set of partial charges generated from our ab initio density functional theory calculations, has been proposed in this study. Molecular dynamics simulations are conducted to determine the thermodynamic properties, transport properties, and the microscopic structures of liquid TBP, TBP/water mixtures, and TBP/n-alkane mixtures. These results are compared with those obtained from four other TBP models, previously described in the literature. We conclude that our refined TBP model appears to be the only TBP model from this set that, with reasonable accuracy, can simultaneously predict the properties of TBP in bulk TBP, in organic diluents, and in aqueous solution. The other models only work well for two of the three systems mentioned above. This new TBP model is thus appropriate for the simulation of liquid-liquid extraction systems in the nuclear extraction process, where one needs to simultaneously model TBP in both aqueous and organic phases. It is also promising for the investigation of the microscopic structure of the organic phase in these processes and for the characterization of third-phase formation, where TBP again interacts simultaneously with both polar and nonpolar molecules. Because the proposed TBP model uses OPLS-2005 Lennard-Jones parameters, it may be used with confidence to model mixtures of TBP with other species whose parameters are given by the OPLS-2005 force field.
authors.affiliation: School of Chemical Engineering and Analytical Science, The University of Manchester , Oxford Road, Manchester M13 9PL, UK.
authors.forename: Junju
authors.initials: J
authors.lastname: Mu
authors.affiliation: Hierarchical Structure Research Group, Materials Sciences Research Center, Japan Atomic Energy Agency (JAEA) , Ibaraki 319-1195, Japan.
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Motokawa
authors.affiliation: School of Chemical Engineering and Analytical Science, The University of Manchester , Oxford Road, Manchester M13 9PL, UK.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Williams
authors.affiliation: Research Center for Neutron Science and Technology, Comprehensive Research Organization for Science and Society (CROSS) , Tokai, Ibaraki 319-1106, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Akutsu
authors.affiliation: Graduate School of Science and Engineering, Yamagata University , Yonezawa, Yamagata 992-8510, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Nishitsuji
authors.affiliation: School of Chemical Engineering and Analytical Science, The University of Manchester , Oxford Road, Manchester M13 9PL, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Masters