Effect of Pressure on the Azeotropes of the Mixture Isobutyl Acetate–Acetic Acid: Vapor–Liquid Equilibrium at 5, 10, and 40 kPa

Abstract In this work, phase equilibrium data for the binary mixture acetic acid (1) + isobutyl acetate (2) were measured at pressures of 5, 10, and 40 kPa using a dynamic recirculation cell (Fischer Labodest VLE model 602). The combined analysis of the new experimental measurements and previously reported experimental data revealed three distinct pressure-dependent regions for the system: a low-pressure region with one azeotrope, an intermediate-pressure region without azeotropes, and a high-pressure polyazeotropic region characterized by two azeotropes. The experimentally obtained data were subjected to a thermodynamic consistency analysis to validate their reliability and were subsequently employed in a regression procedure to estimate a single set of adjusted parameters for the nonrandom two-liquid (NRTL) model over the entire pressure range studied. These parameters can be directly applied in process simulation, separation process design, and the modeling of intensified operations such as reactive distillation involving the acetic acid–isobutyl acetate system.