Phase Behavior and Densities of Propylene + Hexane Binary Mixtures to 585 K and 70 MPa

In this study, we report phase behavior data for propylene + hexane mixtures at temperatures of 295 to 468 K and pressures to 5.5 MPa and high-pressure mixture density data at temperatures of 295 to 584 K and pressures to 70 MPa. Both the phase behavior and density data are simultaneously determined using a variable volume, high-pressure view cell that is coupled with a linear variable differential transformer. The phase behavior and mixture density data are modeled with the Soave–Redlich–Kwong (SRK), Peng–Robinson (PR), modified Sanchez–Lacombe (MSL), and perturbed-chain statistical associating fluid theory (PC-SAFT) equations of state (EoS). The PC-SAFT and MSL EoS provide the best fit of the phase behavior data with a nonzero value of 0.028 for kij. Likewise, the PC-SAFT EoS provides the best fit of the high-pressure mixture density data, though the PC-SAFT equation slightly overpredicts the solution density and the calculated densities are relatively insensitive to changes in kij from zero to 0.028.