EXTENDED LAW OF CORRESPONDING STATES AND THERMODYNAMIC PROPERTIES OF BINARY-MIXTURES IN AND BEYOND THE CRITICAL REGION

A parametric crossover equation of state for pure fluids which incorpo rates the scaling laws asymptotically close to the critical point and is transformed into the regular classical expansion far away from the critical point is adapted to binary mixtures. An isomorphic generaliza tion of the law of corresponding states is applied to the prediction o f the thermodynamic properties and the phase behavior of binary mixtur es over a wide region around the locus of vapor-liquid critical points . Methane-ethane and methane-propane are used as reference mixtures, a nd model parameters for other mixtures are determined completely from excess critical compressibility factors. A comparison is made with the experimental data for twelve binary mixtures. The crossover equation yields a satisfactory representation of the thermodynamic property dat a in a large range of temperatures and densities. Results for the ammo nia-water mixture are consistent with an independent classical correla tion. Published by Elsevier Science Ltd.