Phase behaviour in the vicinity of the three-phase solid–liquid–vapour line in asymmetric nonpolar systems at high pressures

The phenomenon of retrograde melting is investigated. A temperature minimum on the solid–liquid boundary of a constant composition mixture is a necessary condition for the phenomenon to occur. In this work, the criteria for the existence of the retrograde melting phenomena are analysed in terms of volumetric and enthalpic properties of the coexisting phases on the basis of the Gibbs–Konovalow equations. The thermodynamic analysis is supported by new experimental results for the system propane + tetracontane and literature data.