Electric Field Dependence of Phase Equilibria of Binary Stockmayer Fluid Mixtures

Andras Gabor (1) , Istvan Szalai (2)

1 Institute of Physics
2 Institute of Physics

A perturbation theory based study of the effect of an external electric field on the phase equilibrium properties of binary Stockmayer fluids is presented. The dipole-dipole interaction and the applied field are treated as independent perturbations to a Lennard-Jones mixture, and the reference fluid is treated by the van der Waals 1-fluid approximation. A third-order free energy expression in the electric field strength is established, and the dielectric constant is calculated for a needle shaped sample parallel to the field direction. We present and discuss vapor-liquid and liquid-liquid equilibrium curves at a given temperature for some dipolar mixtures exposed to an electric field, including chlorodifluoromethane+difluoromethane and acetonitrile+methanol. A sufficiently high electric field may result in massive shifts of vapour pressures and critical or azeotropic points, and can considerably alter the properties of coexisting phases. The vapor pressure decreases with increasing field strength.

Mots clés: Physical Sciences

Andras Gabor, Istvan Szalai. Electric Field Dependence of Phase Equilibria of Binary Stockmayer Fluid Mixtures. Molecular Physics, 2008, 106 (06), pp.801-812. ⟨10.1080/00268970801961039⟩. ⟨hal-00513180⟩