On the Isothermal-Isobaric Binodal Shape in Ternary Systems

In this work, we compared the shape of a binodal curve in the ternary systems “water – methanol – chloroform”, “water – methanol – dichloromethane”, “water – tert-butanol – toluene”, and “water – 2-butoxyethanol – toluene” in the vicinity of the liquid-liquid critical point (LLCP). We have shown that different approaches to characterize the binodal shape are not equivalent for real ternary systems. The preferred approach involves the calculation of distances based on the tangent to the LLCP and the perpendicular lines to the points on the binodal. The variability in the apparent degree of the binodal curve is revealed, contrary to the known literature.