Deterpenation of Bergamot Essential Oil Using Liquid−Liquid Extraction: Equilibrium Data of Model Systems at 298.2 K

Abstract

The deterpenation of bergamot essential oil can be performed by liquid−liquid extraction using hydrous ethanol as the solvent. A ternary mixture composed of 1-methyl-4-prop-1-en-2-yl-cyclohexene (limonene), 3,7-dimethylocta-1,6-dien-3-yl-acetate (linalyl acetate), and 3,7-dimethylocta-1,6-dien-3-ol (linalool), three major compounds commonly found in bergamot oil, was used to simulate this essential oil. Liquid−liquid equilibrium data were experimentally determined for systems containing essential oil compounds, ethanol, and water at 298.2 K and are reported in this paper. The experimental data were correlated using the NRTL and UNIQUAC models, and the mean deviations between calculated and experimental data were lower than 0.0062 in all systems, indicating the good descriptive quality of the molecular models. To verify the effect of the water mass fraction in the solvent and the linalool mass fraction in the terpene phase on the distribution coefficients of the essential oil compounds, nonlinear regression analyses were performed, obtaining mathematical models with correlation coefficient values higher than 0.99. The results show that as the water content in the solvent phase increased, the k value decreased, regardless of the type of compound studied. Conversely, as the linalool content increased, the distribution coefficients of hydrocarbon terpene and ester also increased. However, the linalool distribution coefficient values were negatively affected when the terpene alcohol content increased in the terpene phase.

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

“…The experimental (liquid + liquid) equilibrium data were obtained according to the methodology of Chiyoda et al [6]. Model systems of essential oils containing terpenic hydrocarbons and oxygenated compounds were prepared by the addition of known quantities of citral to a stock solution of terpenic hydrocarbons.…”

“…This procedure was recently applied to systems containing compounds of essential oils [6] and of vegetable oils [36]. According to this approach, i independent component balances can be written as follows: …”

“…Many techniques, such as supercritical fluid extraction, membrane processing, supercritical adsorption/ desorption, vacuum and steam distillations, enzymatic conversion, selective inclusion and solvent (or liquid-liquid) extraction, have been used to deterpenate essential oils [6][7][8][9][10][11][12].…”

“…Previous studies on optimising the process of deterpenation by liquid extraction have tested many different types of solvents, including ionic liquids [14][15][16]; glycols [17,18]; water [19,20]; aminoethanol [21]; acetonitrile, nitromethane and dimethylformamide [22]; and short chain alcohols, such as methanol [23,24], ethanol [6,19,[25][26][27][28], propanol, and butanol [29].…”

“…In addition, Chiyoda et al [6] and Arce et al [28] determined (liquid + liquid) equilibrium data for systems composed of terpenic hydrocarbons and oxygenated compounds in mixtures of ethanol and water.…”