Combination of supercritical CO₂ and vacuum distillation for the fractionation of bergamot oil

Supercritical CO₂ can be used to separate oxygenated compounds from essential oils. This technique still cannot replace vacuum distillation as an industrial process because of low recoveries and inconsistent results. In the present work, a comparison between the two methods was made in terms of composition, recovery, and color. Vacuum distillation and supercritical CO ₂ are complementary processes for producing high quality oxygenated compounds with high recovery rates. The former is more suitable for removing monoterpenes at low fraction temperatures (≤308 K), and the latter is more suitable for separating oxygenated compounds from pigments and waxes. Consequently, the two methods were combined. For supercritical CO₂ fractionation, the parameters of pressure, temperature gradient, and the ratio of solvent to feed were investigated for the fractionation of oxygenated compounds with high recoveries (≥85%) and without other macromolecules, such as pigments and waxes.