Phase Equilibria in Systems of Morpholine, Acetonitrile, and n -Alkanes

This work presents investigations on the liquid-liquid equilibria (LLE) of ternary systems composed of morpholine, acetonitrile, and an n-alkane at 298.15 K and atmospheric pressure. The investigated n-alkanes were n-hexane, n-heptane, and n-octane. The experimental data were compared to predictions using the perturbed chain-statistical associating fluid theory (PC-SAFT). The predictions are based on pure-component parameters fitted to vapor pressures and liquid densities as well as on binary parameters fitted to binary systems' phase equilibria. For that purpose, the vapor-liquid equilibrium of the morpholine/acetonitrile system was measured at 100 mbar and modeled with PC-SAFT. Binary interaction parameters for acetonitrile/n-alkane systems were obtained from a correlation as a function of the n-alkane carbon number. This correlation, together with the other pure-component and binary parameters, was used to make predictions on ternary systems with n-alkanes longer than n-octane, for which data were taken from literature. All ternary LLE predictions were in satisfactory agreement with experimental data.