Phase Behavior of CO2 + 2,2-dimethylbutane and CO2 + 2-methylpentane from 293 K to 363 K and at Pressures up to 11 MPa

This study is a continuation of a series of works concerning the acquisition of new experimental data related to binary mixtures of branched alkanes with CO₂. A synthetic method was employed to measure phase transition pressures for the systems CO₂ + 2,2-dimethylbutane and CO₂ + 2-methylpentane with an adjustable-volume high-pressure cell. To our knowledge, these binary systems were investigated for the first time in this work. Bubble and dew point pressures were obtained by visual detection at constant composition with an expanded uncertainty ranging from (0.04 to 0.08) MPa. Mixtures were investigated at temperatures ranging from (293.15 to 363.15) K with pressures up to 11 MPa. The Peng-Robinson equation of state was used to correlate the experimental data. An accurate representation of the results has been obtained by using classical mixing rules with temperature-dependent binary interaction parameters regressed against experimental data. The predictive model PPR78 has also provided satisfactory results.