Vapor-Phase Mole Fractions Determined from the P, x Data Using the Margules Equation for High-Pressure Binary Vapor-Liquid Equilibrium Systems Including Carbon Dioxide

摘要

High-pressure P, x data for CO2 + hydrocarbons, methanol, ethanol, and water binaries were correlated using the Margules equation. The average relative difference between experimental data and the correlation was as low as 1 % at T < T_(c1), where T and T_(c1) denote the system temperature and the critical temperature of the lighter component, It was found that the average relative difference of the vapor phase mole fractions from the Margules equation representing the P, x data is 0.6 % for the asymmetric and nonazeotropic binaries. A criterion for identifying the nonazeotropic binaries is proposed. The strength of molecular interactions and molecular order were identified for the azeotropic and zeotropic mixtures using partial molar excess enthalpies and entropies at infinite dilution. A method for the high-precision correlation of infinite dilution activity coefficients is proposed.