Global phase behaviour of binary mixtures of Lennard-Jones molecules

Abstract

The one-fluid model of equation of state and thermodynamic description of boundary states are used to study global equilibrium surface of two-component Lennard-Jones fluids. The global phase diagram for equal size molecules with seventeen separate regions is reported. The new type of phase behaviour is distinguished.The great variety of phase behaviour which was found for binary fluid mixtures is conditioned by intermolecular interaction. The successive theoretical approach to the analysis of the observed phase phenomena in terms of microscopic characteristics is usually restricted by the models of lattice gas in the local regions of the thermodynamic equilibrium sur. face. The global analysis of the equilibrium surface of coexisting fluid phases was reported only for the binary van der Waals mixtures [1,2]. The topological structure, created by the one-fluid van der Waals model, is of such a kind that it reflects many qualities of phase behaviour which were discovered by means of the binary systems that were already studied experimentally. There are, however, some reasons to require this model to be defined more exactly. In the first place, there is no direct correlation between the equation of state parameters and the characteristics of the intermolecular potentials; secondly, essential quantitative discrepancy in predicting the properties for the given binary mixtures is observed; thirdly, the true asymptotic behaviour of the equation of state at the high density limit is not realized. Among more f= ~

Global phase behavior based on the simplified-perturbed hard-chain equation of state

“…The boundary curve between type III A and III H, that was calculated for the first time by Mazur et al, 9 has qualitatively the same shape for the SPHCT equation as it has for the VDW, RK, and CSRK equation. 20,21,23 The right-hand azeotropic critical endpoint curve in the global phase diagram approaches the azeotropic boundary line asymptotically towards ͑,͒ϭ͑1,1͒, where x c →1.…”

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Critical properties of polydisperse fluid mixtures from an equation of state

“…Furman et al [3,4] studied the symmetric ternary lattice gas and the van der Waals lattice gas, and located some new types of phase behavior. Mazur [5] …”

Azeotropy Breaking in Refrigerant Blends with Ionic Liquids

“…Global phase diagrams for all realistic models have an extremely similar structure, particularly for the case of molecules of the same size. For example, the global phase diagrams of such different models as the equation of state for the Lennard-Jones binary fluid [23] and the Redlich-Kwong one fluid model [24] are almost identical, including such sensitive phenomena as the presence of closed immiscibility regions. Accordingly, most of assumptions and conclusions based on the studied models of phase behavior can be transferred to other cases.…”