Vapour–liquid equilibrium of binary systems containing pentafluorochemicals from 363 to 413 K: Measurement and modelling with Peng–Robinson and three SAFT-like equations of states

New sets of data are provided to characterize the phase equilibrium of new mixtures containing fluorochemicals and show their potential in energy recovery applications, as industrial heat pumps. Isothermal Vapour–Liquid Equilibrium data have been measured for R245fa + isopentane, and R365mfc + isopentane systems. Measurements were performed for four isotherms with pressure from 0.4 to 2.9 MPa. The data are correlated using different models (Peng–Robinson, PC-SAFT, polar PC-SAFT and SAFT-VR equations of state) and all four approaches can accurately describe the VLE. A very good description of the VLE for the pure components and the mixtures can be obtained by representing the R245fa and R365mfc molecules either as non-polar associating compounds or as non-associating dipolar molecules. To confirm the experimental values of the dipoles used in polar PC-SAFT, we performed DFT calculations of the permanent dipoles of the molecules and a good agreement with the experimental values is found for R245fa, while two different values corresponding to two different conformations were found for R365mfc.