Solubility of CO2 in branched alkanes in order to extend the PPR78 model (predictive 1978, Peng–Robinson EOS with temperature-dependent kij calculated through a group contribution method) to such systems

A high pressure, variable-volume visual cell was used to perform static measurements of phase equilibria involving carbon dioxide and four different alkanes: n-heptane, 2,2,4-trimethyl pentane (isooctane), 2,5-dimethyl hexane and 3-methyl pentane. Different temperatures ranging from 278.15 to 413.15 K were selected. The bubble point pressures, ranging from 12 to 134 bar were measured at carbon dioxide mole fractions between 0.23 and 0.91. The experimental data were compared with correlations obtained with a simplified version of the PPR78 model in which each molecule has been considered as a single group. Such a model is able to predict with quite high accuracy our data whatever the temperature.