Liquid-liquid- und gas-liquid equilibria data as well as information on interfacial properties are needed to investigate the applicability of thermomorphic solvent systems to the hydroformylation of olefins. The perturbed chain polar statistical associating fluid theory (PCP-SAFT) combined with the density gradient theory was shown to be highly appropriate to calculate these data. Only one set of parameters for each component was necessary to describe the different thermodynamic properties. Thereby, also experimental data which were not involved in parameter fitting were reproduced successfully. That is, the modeling tool can be applied to reliably generate data for experimentally unexplored thermodynamic states.