The CO2 + 2,3,4-trimethylpentane and CO2 + 2,2,4,6,6-pentamethylheptane binary systems: high–pressure phase equilibria measurements

Two binary systems containing CO 2 and a branched alkane were newly studied in this work: CO 2 + 2,3,4-trimethylpentane and CO 2 + 2,2,4,6,6-pentamethylheptane. Their fluid phase behavior was investigated using a high-pressure variable-volume cell and a synthetic method. Saturation pressures were visually measured from (293.15 et 363.15) K and for 10 different CO 2 mole fractions for both mixtures. Whatever the considered system, no liquid-liquid immiscibility was observed in this temperature range, suggesting a continuous vapor-liquid critical curve between the pure components critical points. A total of 160 points were acquired: 149 bubble points and 11 dew points. These new experimental data were satisfactory modeled by using the Peng-Robinson equation of state with a temperature-dependent interaction parameter, k ij ( T ), fitted against the data.