(ρ, VE, T) Measurements of the Ternary Mixture (Dibutyl Ether + 1-Heptanol + Heptane) at Temperatures up to 393.15 K and Pressures up to 140 MPa and Modeling Using the Peng–Robinson and PC-SAFT Equations of State

New measurement density data (1360 points) for dibutyl ether (1) + 1-heptanol (2) + heptane (3) were measured at various temperatures, T (298.15–393.15) K, and various pressures, p (0.1–140) MPa, adopting an Anton-Paar densimeter (DMA HPM). The excess molar volumes, V E, of the studied ternary system were derived from the measured density data. Subsequently, they are calculated with the Singh and Redlich–Kister equations. V E values were employed to obatin the different interactions implied in the mixture. The Peng–Robinson and the perturbed chain-statistical association fluid theory (PC-SAFT) equations of states were performed for their potential to correlate and predict the experimental density for the ternary mixture. The PC-SAFT parameters of pure compounds that constituted the studied ternary mixture were regressed by the measured data of density of each pure compound.