High pressure phase equilibrium measurements for binary systems CO2 + 1-pentanol and CO2 + 1-hexanol

Abstract This work reports phase equilibrium measurements for the systems CO 2 (1) + 1-pentanol(2) and CO 2 (1) + 1-hexanol(2). Experiments were carried out using a high pressure variable-volume view cell with operating temperatures ranged from 303.15 K to 373.15 K and pressures up to 17.05 MPa for the system CO 2  + 1-pentanol, and 303.15 K to 353.15 K with pressures up to 16.2 MPa for the system CO 2  + 1-hexanol. The CO 2 molar fractions were ranged from 0.3987 to 0.9192 for the system CO 2 (1) + 1-pentanol(2) and from 0.3926 to 0.9800 for the system CO 2 (1) + 1-hexanol(2), respectively. Only vapor–liquid (VL) phase transitions were observed for the system CO 2 (1) + 1-pentanol(2), while for the system with 1-hexanol(2) vapor–liquid (VL), liquid–liquid (LL) and vapor–liquid–liquid (VLL) phase transition were observed. The experimental data sets were modeled using the Peng–Robinson equation of state with a classical van der Waals quadratic mixing rule (PR-vdW2) and with Wong–Sandler (PR-WS) mixing rule, and they were compared with predicted values using the Predictive Soave–Redlich–Kwong (PSRK) equation of state. PR-WS model provided a better fitting to experimental data for both systems modeled.