The paper presents new experimental data on the chemical equilibrium in the system n-propanol + acetic acid + n-propyl acetate + water at 293.15 and 353.15 K, and the data on liquid–liquid equilibrium at 353.15 K. Based on the experimental and literature data, the possibilities that chemical equilibrium exists in a homogeneous or heterogeneous region of compositions has been analyzed. The temperature shift of chemical and phase equilibria and the values of the thermodynamic constants of chemical equilibrium are discussed.