STUDIES ON VAPOR-LIQUID-EQUILIBRIUM NEAR THE CRITICAL LINE FOR FLUID MIXTURES - DESCRIPTION OF COEXISTENCE DENSITIES OF BINARY-MIXTURES

Two expressions for describing the coexistence densities of vapor-liquid equilibrium binary mixtures are formulated by employing renormalization group theory predictions for the thermodynamic properties of fluids near the critical point. A least square fit of coexistence density data is made by using general and relatively simple equations and yields calculated values that are in excellent agreement with the experimental data over a wide range of systems, pressures and temperatures. The method presented here is also able to predict the critical volume and critical pressure of binary mixtures.