Liquid-Liquid Equilibrium for System Composed of α-Pinene, α-Terpineol and Water

The major component of turpentine is α-pinene and the main hydration product of α-pinene is α-terpineol. To obtain the optimal process design of α-terpineol production, some initial information regarding the principle of the thermodynamics and phase equilibrium are required. The aim of this paper is to present liquid-liquid equilibrium (LLE) of system containing α-pinene, α-terpineol and water. Ternary LLE for α-pinene, α-terpineol and water system was determined by experiment at the temperatures of 301, 327 and 353 K and atmospheric pressure. The three component mixture was stirred for about 30 min, then the mixture was left for about 2 h for complete phase separation. The composition of both phases was analyzed by using a Gas Chromatograph. The thermodynamic equilibrium models were proposed. LLE model in this study includes activity coefficient model based on NRTL and UNIQUAC models. The NRTL model (α = 0.2) correlates the LLE data for the system of α-pinene + α-terpineol + water at the temperatures 301, 327 and 353 K with RMSD of 0.5464%, 0.000169% and 0.0054%, respectively. The UNIQUAC model correlates the LLE data for the system of α-pinene + α-terpineol + water at the temperatures 301, 327 and 353 K with RMSD of 0.756%, 1.314% and 1.6615%, respectively. The LLE data for the system of α-pinene + α-terpineol + water were successfully correlated using the NRTL and UNIQUAC models at that temperatures