Vapor-liquid equilibria in the 1-methylpyrrolidine + 1-butylimidazole binary system: Experimental measurements and theoretical modelling

Abstract

In this study, a comprehensive investigation of the 1-methylpyrrolidine + 1-butylimidazole binary system was conducted to establish a valuable foundation for process design. Isobaric binary vapor − liquid equilibrium (VLE) data was measured (80 data points) at 50.0, 20.0, 10.0, and 7.5 kPa using dynamic equilibrium cell (VLE 602) and found that no azeotrope existed throughout the entire operating pressure range. Thermodynamic consistency was validated using the Redlich − Kister area test (9.56801%). The vapor pressure of 1-butylimidazole was determined through direct measurement (12 data points) of the equilibrium temperature at different pressures and the Antoine equation parameters were regressed based on the acquired data. The VLE data were regressed using maximum likelihood (ML) method, and binary interaction parameters (BIP) were estimated for NRTL–HOC, UNIQUAC, Van Laar, and Wilson models. The model validation demonstrated consistency between calculated and experimental values for temperature and mole fraction of the vapor phase. In addition, dipole moment (μ) values were evaluated by quantum chemical calculations using the Hartree–Fock (HF) method through GAMESS package. The density (12 data points), the sound velocity (12 data points), the refractive index (3 data points), and the normal boiling points (3 data points) were also measured for binary mixtures and pure components.