A dispersion force model that accurately predicts low-pressure vapor–liquid equilibria for 65 alkane/alkane binaries

A dispersion force (DF) model was examined to determine if it can accurately predict the VLE data of alkane/alkane binaries in the literature. A total of 65 alkane/alkane binaries was found in the DECHEMA Chemistry Data Series. The mole fraction of the alkane in the liquid phase, xi, ranged from 0.1 to 0.9 in 62 binaries. VLE data were produced using Margules interaction parameters shown in the DECHEMA Data Series. viations between the representative pressure data and the pressures predicted by the DF, the ideal solution (IS) and the Flory–Huggins (FH) models, (AAD)P, are close to each other in the case of ideal solutions. However, the (AAD)P values calculated from the DF, IS and FH models for non-ideal solutions were 1.1%, 2.2% and 3.6%, respectively; the DF model accurately predicts the VLE of alkane/alkane binaries even if the system is under non-ideal conditions. The FH model less satisfactorily predicts the VLE data than the IS model for the non-ideal solutions. The entropy–enthalpy compensation holds for the partial molar excess quantities.