Isothermal Vapor-Liquid Equilibrium Data for Binary Systems Containing Carbon Dioxide at High Pressures: Methanol-Carbon Dioxide, n-Hexane-Carbon Dioxide, and Benzene-Carbon Dioxide Systems

Isothermal vapor-liquid equilibrium data for the systems methanol-carbon dioxide, n-hexane-carbon dioxide, and benzene-carbon dioxide were measured by a static method at 25' and 4OoC. By use of the Lewis rule and the RedlichKwong equation of state for carbon dioxide in the vapor phase, the activity coefficients in the liquid phase and the fugacity coefficients in the vapor phase were evaluated from thermodynamic relationships. The isothermal vapor-liquid equilibria at high pressures for binary systems containing carbon dioxide were reported in previous papers, in which methanol-carbon dioxide and acetone-carbon dioxide systems were measured by a vapor recirculation method (3), and ethyl ether-carbon dioxide and methyl acetate-carbon dioxide systems by a static method In this study the vapor-liquid equilibria for three binary systems of methanol-carbon dioxide, n-hexane-carbon dioxide, and benzene-carbon dioxide were measured at 25' and 4OoC by the static method. The activity coefficients in the liquid phase and fugacity coefficients in the vapor phase were determined by using the Lewis rule and the Redlich-Kwong equation of state for carbon dioxide in the vapor phase. The liquid activity coefficients in the methanol-carbon dioxide system are the largest of the three systems, though those in n-hexane-carbon dioxide and benzene-carbon dioxide are also considerably large. Experimental