This report presents a vapor–liquid equilibrium (VLE) study for the binary system 1-butanol + dibutyl ether, performed using Aspen Plus. The objective was to select an appropriate thermodynamic model, produce a T–x–y diagram at 1 atm, and analyze the variation of azeotropic temperature, azeotropic composition, and azeotropic pressure over the ranges: P = 10–500 kPa and T = 20–200 °C. Results are presented with plots, a concise discussion of trends, and practical implications for distillation separation design
