Liquid-liquid equilibrium for 1-butanol-water-KF and 1-butanol-water-K₂CO₃ systems

Abstract

KF or K₂CO₃ was added into the 1-butanol-water system and two phases were formed: water-rich phase (water phase) and 1-butanol-rich phase (1-butanol phase). The liquid-liquid equilibrium (LLE) data for 1-butanol-water-Kf and 1-butanol-water K₂CO₃ systems were measured at 25°C and showed that 1-butanol phase contained negligible salt and water phase contained negligible 1-butanol when the concentrations of KF and K₂CO₃ in the water phase were equal to or higher than 27.11% and 31.68%, respectively. Thus water could be separated efficiently from 1-butanol-water by adding KF or K₂CO₃ into the system. A theoretical calculation of LLE data was calculated by using the Pitzer theory to get water activity in the water phase, and by the models, such as the Wilson, NRTL or the UNIQUAC for the 1-butanol phase. For 1-butanol-water-KF system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and Wilson equation, while for 1-butanol-water-K₂CO₃ system, the experimental data were found in good agreement with the calculated results by using Pitzer theory and UNIQUAC equation.