Thermodynamics of ternary mixtures exhibiting tunnel phase behaviour Part 2.—n-Hexane–n -decane–propanenitrile

Abstract

The shape of the two-liquid-phase coexistence region in the phase prism of the ternary mixture n-hexane–n-decane–propanenitrile has been determined by measurements of phase-separation temperatures for mixtures in three quasibinary slices each with constant n-decane:n-hexane volume ratio. These results were used along with the coexistence curve results of Arriaga-Colina, McLure, Clements and Hill for the binary mixtures n-hexane–propanenitrile and n-decane–propanenitrile to characterise the topology of the composition–temperature ternary phase diagram. A crude method for the estimation of the tielines for the n-decane:n-hexane volume ratio=3:1 quasibinary slice has revealed that they do not lie in the plane of the quasibinary slice. Furthermore, the positions of the tielines change with temperature, tending at higher temperatures to become more parallel to the nearer binary face of the phase diagram.