Toluene model for molecular dynamics simulations in the ranges 298 <T (K) <350 and 0.1 <P (MPa) <10

An all-atom model for toluene is presented in the framework of classical molecular dynamics (MD). The model has been parametrized under the GROMOS96 force field to reproduce the physicochemical properties of the neat liquid. Four new atom types have been introduced, distinguishing between carbons and hydrogens of the aromatic and of the CH3 aliphatic groups. The thermodynamic and kinetic properties in the liquid phase have been calculated within a temperature and a pressure range of 298 <T (K) <350 and 0.1 <P (MPa) <10, respectively. The average relative deviations from the experimental data in the range of temperatures and pressures considered are 0.5%, 7% and 25% for the density, vaporization enthalpy and viscosity, respectively. The free energy of hydration has been estimated as -5.8 kJ mol-1, in good agreement with the experimental value of -3.6 kJ mol-1. Structural investigations have been conducted to understand the structure of the liquid and compared to experimental data. Parallel stacking of the aromatic planes with antiparallel disposition of the CH3 groups has been found. The presented toluene model is suitable for MD simulations in a range of pressures and temperatures interesting for industrial processes and organic chemistry (i.e., polymer and dendrimer dynamics)