Parametrization of 2,2,2-trifluoroethanol based on the generalized AMBER force field provides realistic agreement between experimental and calculated properties of pure liquid as well as water-mixed solutions

J Phys Chem B. 2014 Sep 4;118(35):10390-404. doi: 10.1021/jp505861b. Epub 2014 Aug 25.

Abstract

We present a novel force field model of 2,2,2-trifluoroethanol (TFE) based on the generalized AMBER force field. The model was exhaustively parametrized to reproduce liquid-state properties of pure TFE, namely, density, enthalpy of vaporization, self-diffusion coefficient, and population of trans and gauche conformers. The model predicts excellently other liquid-state properties such as shear viscosity, thermal expansion coefficient, and isotropic compressibility. The resulting model describes unexpectedly well the state equation of the liquid region in the range of 100 K and 10 MPa. More importantly, the proposed TFE model was optimized for use in combination with the TIP4P/Ew and TIP4P/2005 water models. It does not manifest excessive aggregation, which is known for other models, and therefore, it is supposed to more realistically describe the behavior of TFE/water mixtures. This was demonstrated by means of the Kirkwood-Buff theory of solutions and reasonable agreement with experimental data. We explored a considerable part of the parameter space and systematically tested individual combinations of parameters for performance in combination with the TIP4P/Ew and TIP4P/2005 water models. We observed ambiguity in parameters describing pure liquid TFE; however, most of them failed for TFE/water mixtures. We clearly demonstrated the necessity for balanced TFE-TFE, TFE-water, and water-water interactions which can be acquired only by employing implicit polarization correction in the course of parametrization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diffusion
  • Gases / chemistry
  • Lipids / chemistry
  • Models, Chemical
  • Molecular Dynamics Simulation
  • Solvents / chemistry
  • Static Electricity
  • Trifluoroethanol / chemistry*
  • Viscosity
  • Volatilization
  • Water / chemistry*

Substances

  • Gases
  • Lipids
  • Solvents
  • Water
  • Trifluoroethanol