Phase equilibrium diagrams classification

Figure 14.10 The five types of (fluid + fluid) phase diagrams according to the Scott and van Konynenburg classification. The circles represent the critical points of pure components, while the triangles represent an upper critical solution temperature (u) or a lower critical solution temperature (1). The solid lines represent the (vapor + liquid) equilibrium lines for the pure substances. The dashed lines represent different types of critical loci. (l) [Ar + CH4], (2) [C02 + N20], (3) [C3H8 + H2S],...

These diagrams can take various forms depending on the properties of the solute and solvent molecules. A very thorough study of the possibilities has been made by van Konynenburg and Scott [15] who identified six principal types of fluid/fluid equilibrium behaviour in binary systems. For a complete discussion, reference should be made to the above study and also to the works of Rowlinson [16] and other authors [17-19]. In the discussion below a simplified classification is used to describe typical forms of fluid/fluid phase behaviour in the near-critical region. (Some readers may find it helpful to read... 

Oligomer systems are typically described by phase diagrams of an amorphous equilibrium according to classification by S.P. Papkov [168,206]. Sometimes amorphous-crystalline equilibrium [134,165] is observed [134,165]. The majority of oligomer system phase diagrams is asymmetric and has upper critical solubility temperature (UCST). 

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