(335f) A Revision of Classical Force Fields for Tri-N-Butil Phosphate Molecular Dynamics Simulations

Tri-n-butil phosphate (TBP) is a solvent extraction ligand commonly used in the separation of metals from acidic aqueous solutions in nuclear chemical engineering. It’s science and technology has been reported in a well-known 4-volume book series in the mid 1980’s but advances in computing had not been used to shed light at atomistic level phenomena at that point in time. Starting in the mid 1990’s, and continuing to 2010, molecular dynamics simulations were used to provide atomistic insight on solvent extraction. In the past decade a number of articles appeared in the literature employing classical molecular dynamics for studying various aspects of chemical complexation in solvent extraction involving TBP. It is instructive now, in view of growing computing power and access to open-source scientific software, for a computational revision of proposed force fields to be carried out with the intent of further advance the science and technology of TBP in more realistic scenarios where competing extraction of acid, water, and additional metals take place.

This work is reproducing and revising significant classical force fields published in the open literature in accord with current open science standards to compute thermochemical properties of TBP from atomistic simulations. It is expected that this work will provide recommendations on force fields for TBP to be used in additional studies. Our own past work has revelead an important effect of the electric dipole moment of TBP in modifying the interfacial property of aqueous/organic interfaces that leads to the extraction of water. We expect a similar effect on the extraction of other solutes therefore additional research in this direction is warranted. Past work of interest and basis for this project:

Ye, X., Cui, S., de Almeida, V. F., Khomami, B., 2009 Interfacial complex formation in uranyl extraction by tributyl phosphate in dodecane diluent: a molecular dynamics study, J. Phys. Chem. B, 113, pp. 9852–623

Ye, X., Cui, S., de Almeida, V. F., Hay, B. P., Khomami, B., 2010, Uranyl nitrate complex extraction into TBP/dodecane organic solutions: a molecular dynamics study Phys. Chem. Chem. Phys. 12, pp 15406–94

Ye, X., Cui, S., de Almeida, V. F., Khomami, B. 2013 Molecular Simulation of Water Extraction into a Tri-n-Butylphosphate/n-Dodecane Solution J. Phys. Chem. B 117 pp. 14835–415

Cui, S., de Almeida, V. F., Hay, B. P., Ye, Xianggui, Khomami, B. 2012 Molecular Dynamics Simulation of Tri-n-Butyl-Phosphate Liquid: A Force Field Comparative Study J. Phys. Chem. B 116 pp. 305–136

Ye, X., Cui, S., de Almeida, V. F., Khomami, B. 2013 Effect of Varying the 1–4 Intramolecular Scaling Factor in Atomistic Simulations of Long-Chain N-Alkanes with the OPLS-AA Model J. Mol. Model. 19 pp 1251–58