Critical points in ternary systems

Phase equilibria and pressure-temperature coordinates of critical points in ternary systems were taken with a high-pressure apparatus based on a thermostated view cell equipped with two liquid flow loops which has been described in detail elsewhere [3]. The loops feed a sample valve which takes small amounts of probes for gas-chromatographic analysis. In addition to temperature, pressure and composition data, the densities of the coexisting liquid phases are measured with a vibrating tube densimeter. Critical points were determined by visual oberservation of the critical opalescence. 

While the melting point depressions for binary systems may not seem to be of great concern because most studies are performed near the solvent critical point, in ternary systems with two solids and one supercritical fluid the melting points may be lowered significantly. For example, the phase behavior of two solids in contact with a supercritical fluid is shown in Figure 9. The dotted lines represent the phase behavior in the pure systems and the binary systems discussed above. New phase boundaries in the ternary system are indicated by the solid lines. Note that the... 

N(Li = L2-G) and R (Li = G-L2) are the critical endpoints in binary subsystems LN (Li = L2-G-S), NN (Li = L2-G) and NR (Li = L2 = G) are the nonvariant critical points in ternary systems. One-dotted-dashed line is the ternary mono variant critical curve Li = L2-G, two-dotted-dashed line is the ternary mono variant critical curve Li = G-L2 dashed line is the approximate compositions of liquid phase in equilibria L1-L2-G-S and L-G-S. 

Kahlweit, M., Strey, R. and Firman, P., Search for tri-critical points in ternary systems water-oil-nonionic amphiphile, J. Phys. Chem., 90, 671 (1986). 

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See also in sourсe #XX -- [ , , ]

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