Fluid-phase equilibria in binary systems containing an ionic liquid. Application of the Percus–Yevick–van der Waals equation of state

Following some simplifications to reduce the computational effort, the Percus–Yevick–van der Waals equation of state is used to calculate the isothermal total pressure of a binary liquid system containing one volatile nonelectrolyte liquid and one nonvolatile ionic liquid. Pure-component parameters a and b are found from pure-component enthalpy-of-vaporization and liquid-density data. The single binary parameter a12 is obtained from Henryʹs constant for the nonelectrolyte in the ionic liquid. For 10 binary systems, calculated total pressures are in good agreement with experiment although in a few systems observed total pressures are slightly higher than those calculated in the region where the ionic liquid is dilute. Brief attention is given to a few binary systems with a miscibility gap.