Experimental and process simulation study of deterpenation of bergamot essential oil using 1-ethyl-3-methylimidazolium acetate

This work combines experimental measurements and process simulation on the deterpenation of bergamot essential oil using ionic liquids as solvents. Partition coefficients for different key components of citrus essential oils between 1,3-dialkylimidazolium acetates and limonene (the major terpene component in most citrus essential oils) were measured, showing that some key terpenoids, such as ester derivatives, are difficult to extract. Then, deterpenation of bergamot essential oil (rich in an ester terpenoid) was investigated using 1-ethyl-3-methylimidazolium acetate ([C 2 mim][OAc]). Liquid-liquid equilibrium data at 298.2 K were measured for the ternary systems containing two of the most representative bergamot essential oil constituents (limonene, linalool, linalyl acetate) and [C 2 mim][OAc] as solvent. The experimental data were successfully correlated using the non-random two-liquid model, providing binary interaction parameters for reliable process simulation in Aspen Plus®. Both experiments and simulations demonstrate that [C 2 mim][OAc] provides an efficient separation of linalool from limonene, while recovery of linalyl acetate is limited. Optimal performance was achieved with a solvent-to-feed ratio of 1 and two equilibrium stages, maximising the purity of the deterpenated oil in the extract and the recovery of terpenoids. The simulations show good agreement with experimental extractions carried out using both synthetic and commercial bergamot essential oils. Overall, the study highlights both the potential and limitations of [C 2 mim][OAc] for efficient citrus essential oil valorisation, providing robust and valuable insights for process optimisation.