Extraction of oxygenated compounds from crude citrus latifolia peel oil using ethanol/water mixtures as solvents: Phase equilibrium and continuous equipment operation

Abstract

Abstract Citrus latifolia (acid lime) essential oil, an important commodity in the international market, was fractionated by solvent extraction. New liquid–liquid equilibrium (LLE) data for systems composed of crude acid lime essential oil (CALEO), ethanol, and water at T = (298.2 ± 0.1) K were acquired for different water contents in the solvent and mass ratios between the solvent and CALEO (S/EO). The performance of the NRTL parameters available in the literature was evaluated by comparing the predicted LLE phases compositions with the experimental data. Higher water content in the solvent led to lower migration of the components from the raffinate to the extract phase but increased the solvent selectivity for oxygenated compounds. Low S/EO also decreased the migration of the components. The predicted composition exhibited satisfactory results, with global deviations in mass fraction up to 0.02. The CALEO was also fractionated in a perforated rotating disc contactor, using ethanol/water mixtures as solvents. The process performance was evaluated by experimental and simulated extraction indices. As in the LLE, additional water in the solvent and lower solvent to feed mass flow ratio (S/F) led to less extraction of the components, but higher experimental Folds were achieved (6-fold using ethanol 40 and 8-fold using 50% w/w water). Finally, greater water content in the solvent was also related to higher experimental values of density, viscosity and surface tension, especially for the extract phases, contributing for better operational conditions.