Note on the properties altered by application of a Péneloux–type volume translation to an equation of state

Since the pioneering work of Professor André Péneloux, volume translations are often applied to cubic equations of state with the aim of improving the description of volumetric properties. Such translations are either constant or temperature-dependent. In any case, it is well-known that both the translated and untranslated models return the same vapor pressure for a given temperature but lead to different saturated molar volumes. Being aware of the invariance of the calculated vapor pressure, it was decided to investigate which properties among the enthalpy, the entropy, the internal energy, the heat capacities, the speed of sound, the property changes on vaporization and many others were altered by a volume translation. All these state functions are indeed volume-dependent and the influence of the translation on their values needs to be clarified. This is particularly important to understand on which experimental data the volume translation should be fitted on.

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