Experimental Study and Modeling of the Isothermal VLE Properties of the Supercritical C₃H₈ + Aniline Mixture at High Temperatures and High Pressures

This paper presents new experimental VLE property data of aniline in the near and supercritical propane at five selected isotherms of (393.15, 413.15, 433.15, 473.15, and 523.15) K over the pressure range of (0.99-11.48) MPa. The measurements were performed by using a high-temperature and high-pressure optical cell. The combined expanded absolute and relative uncertainty of the temperature, pressure, and concentration measurements at 0.95 confidence level with a coverage factor of k = 2 is estimated at 0.15 K, 0.2%, and 3%, respectively. The measured VLE data were used to estimate the critical curve P_C-T_C data. For the mixture, measured equilibrium vapor (y) and liquid (x) phase compositions were used to calculate the activity coefficient of aniline in the liquid phase as a function of temperature at three selected constant pressures. The performances of PC-SAFT attached by the 2B association scheme, the simplest association-neglecting form of CP-PC-SAFT and the Peng-Robinson EoS in estimating the pure compound properties of aniline and the currently measured VLE data were compared.