Estimation of Diffusion Coefficient of Benzene/Hexane Mixtures by Molecular Dynamics Simulation

Molecular dynamics simulations have been performed in this study to predict the diffusion coefficient of benzene in hexane and vice versa by Materials Studio software. COMPASS force field has been applied to the system for optimization of the structures of benzene and hexane molecules. To model and calculate the van der Waals and electrostatic potential energies, a group-based summation method has been utilized. In order to predict the diffusion coefficient, firstly the simulation time and the force field have been optimized. In all simulations, Ewald and Atom-based summation methods were employed to calculate electrostatic and van der Waals potential energies. The optimized simulation times for the diffusion of benzene in hexane with the mole fraction of 0.2, and the diffusion coefficient of hexane in benzene with the mole fraction of 0.8, have been obtained to be 35 and 25 ps, respectively. In addition, the best force field to predict the diffusion coefficient has been identified to be “Pcff”.