Validating the Darken Relation for Diffusivities in Fluid Mixtures of Varying Densities by Use of MD Simulations

Molecular Dynamics (MD) simulations have been carried out to determine the self‐diffusivities, Di,self, of the pure hydrocarbons methane (C1), ethane (C2), propane (C3), and n‐hexane (nC6) at various fluid densities. The MD simulations are in reasonable agreement with published experimental data. The influence of fluid density on both Di,self and the Maxwell‐Stefan (M‐S) diffusivities, Đij, in binary C1‐C2, C1‐C3, C2‐C3, and C1‐nC6 mixtures was also investigated. The MD simulations show that the M‐S diffusivities in binary fluid mixtures can be estimated with good accuracy using the Darken relation.