Density and Surface Tension of Propanol and Propanol-Water Mixtures Using Molecular Dynamic Simulations

Abstract

Optimized Potentials for Liquid Simulations-All Atoms (OPLS-AA) and Transferable Potentials for Phase Equilibria-United Atom (TraPPE-UA) have been examined with two water models (TIP4P and SPC/E) to estimate the density and the surface tension for unary propanol and binary propanol-water mixtures. While both models predicted the experimental trend of the density for the unary system as a function of temperature and for the binary mixtures as a function of mole fraction of propanol, TraPPE-UA shows better fit with experimental data of pure propanol at low temperaturesrange (200K-300K). On the other hand, for the surface tension, TraPPE-UA provides a better agreement with the experimental data for pure propanol, while OPLS-AA shows better agreement for the binary mixtures at 300K for the entire mole fraction of propanol (0-1). The density profiles of the mixtures show that the structure of the mixtures changes from core-shell at low mole fractions of propanol to well-mixed at high concentrations of propanol.

Keywords:Molecular dynamics, Surface tension, Liquid density, OPLS-AA, TraPPE-UN.

PACS: 61.20. Ja, 68.03.Cd, 86.15.N. 61.20. Ja, 68.03.Cd, 86.15.N.