Common Intersection Points of Binary Mixtures:  Unlike Interactions Compared to Like Ones

Abstract

In the present work the existence of a common compression factor point for binary mixtures has been investigated, both experimentally and theoretically. We found that the linear isotherm regularity (LIR) is able to predict the common compression factor point and the common bulk modulus point for binary mixtures, as well as pure dense fluids. An important conclusion deduced from this work is that a physical interpretation for such points may be given using LIR. The LIR along with the mean geometric approximation (MGA) have been used to relate the density at the common points of a mixture to those of its pure components. The numerical investigation shows that such a relation may be represented by a quadratic function in terms of the system composition for most mixtures. However, we have found that such a quadratic relation is generally valid for all investigated mixtures. An important result obtained from this work is that we may get information about the magnitude of interactions between unlike molecules, compared to those of like interactions. Such a result can be used to predict the deviation of a solution from ideality without having any vapor pressure data.

An Application of the Linear Isotherm Regularity (LIR)

“…The upper density limit is less certain but seems to be the freezing line of compressed liquids and at least about twice the Boyle density for supercritical fluids. Additionally, the LIR has been found to be valid for binary mixtures as well and used to predict the gradual transition from metallic to nonmetallic successfully …”

Common compression factor and bulk modulus quiescence points of liquid cesium

“…The success of the second method leads to the failure of the first one in that the constant b, the van der Waals covolume, is actually a temperature dependent parameter as derived by the statistical mechanical approach. [6,7] Also by the application of the Linear Regularity Isotherm (LIR) [8,9], common intersection points have been observed for dense molecular liquids and their mixtures.…”