Experimental and Modeling Study of Binary and Ternary Mixtures of Propan-1-ol, Pyridine, and Nitrobenzene at T = (293.15, 298.15, 303.15, 313.15, and 323.15) K and Atmospheric Pressure

Densities and sound speeds of the ternary system {propan-1-ol + pyridine + nitrobenzene} were measured at T = (293.15, 298.15, 303.15, 313.15, and 323.15) K and atmospheric pressure over the entire composition range, together with those of the corresponding binaries. Excess molar volumes and excess isentropic compressibilities, derived from the experimental data, were correlated using the Redlich–Kister and Cibulka equations for binary and ternary systems, respectively. The composition and temperature dependence of these properties provided information on intermolecular interactions and structural effects. Densities were modeled with the predictive PC-SAFT equation of state, while Schaaff’s Collision Factor Theory and Nomoto’s relation predicted sound speeds. The Jouyban-Acree model correlated density, sound speed, and their derived properties (isentropic compressibility and isobaric thermal expansivity) with a small number of adjustable parameters. Ternary excess properties were further compared with predictions from symmetric (Kohler, Muggianu) and asymmetric (Hillert, Toop) geometric models. Model performance was assessed using statistical indicators, demonstrating the applicability of both theoretical and empirical approaches to describe the thermophysical behavior of these mixtures.