Fractionation of lemon essential oil by solvent extraction: Phase equilibrium for model systems at T = 298.2 K

The fractioning of lemon essential oil can be performed by liquid–liquid extraction using hydrous ethanol as a solvent. A quaternary mixture composed of limonene, γ-terpinene, β-pinene, and citral was used to simulate lemon essential oil. In this paper, we present (liquid + liquid) equilibrium data that were experimentally determined for systems containing essential oil compounds, ethanol, and water at T = 298.2 K.The experimental data were correlated using the NRTL and UNIQUAC models, and the mean deviations between calculated and experimental data were less than 0.0053 in all systems, indicating the accuracy of these molecular models in describing our systems.The results show that as the water content in the solvent phase increased, the values of the distribution coefficients decreased, regardless of the type of compound studied. However, the oxygenated compound always showed the highest distribution coefficient among the components of the essential oil, thus making deterpenation of the lemon essential oil a feasible process.

► Deterpenation of lemon oil by solvent extraction using hydrous ethanol.
► Limonene, γ-terpinene, β-pinene, and citral were used to simulate the oil.
► Citral shows a higher distribution coefficient than the hydrocarbons.
► Terpenic hydrocarbons exhibit very similar phase separation behaviour.
► NRTL and UNIQUAC models provided a good description of the phase equilibrium.