Vapor-Liquid Equilibrium Measurements of Ethanol and n -Nonane or n -Decane Binary Mixtures with Large Relative Volatility

A specialized still was used for the measurement of vapor-liquid equilibrium (VLE) data by the dynamic-analytic approach at low pressures. The specialized apparatus improves the measurement of VLE in high relative volatility systems. Isothermal measurements were conducted for the ethanol (1) + n-nonane (2) systems at 323.21, 333.21, and 343.21 K and the ethanol (1) + n-decane (2) systems at 328.17, 338.17, and 348.16 K. The experimental data was modeled by the combined approach using the NRTL activity coefficient model for the liquid phase and with the virial equation of state for the vapor phase with the Hayden and O'Connell correlation. The experimental data was fitted by minimizing the pressure residual. UNIFAC predictions were also conducted, and there was significant discrepancy between experimental and predicted data, highlighting the importance of precise experimental data in these types of systems. Thermodynamic consistency tests showed all data to be consistent.