High-pressure gas–liquid equilibrium of the system carbon dioxide–β-caryophyllene at 50 and 70 °C

New experimental data of high-pressure gas–liquid equilibrium for the system carbon dioxide–β-caryophyllene are provided. The equilibrium measurements were carried out at 50 and 70 °C, for pressures which are particularly relevant in the context of the supercritical deterpenation of lemon essential oil (from 8.8 to 15.6 MPa). Both the liquid and the gas equilibrium composition were measured. The experiments were carried out using a two-chamber gas-phase recirculation apparatus of 340 cm3. The experimental results agree well with the few experimental data available in the literature and extend the experimental knowledge on this system. The measured data were satisfactorily correlated by means of the Peng–Robinson equation of state, expressing the mixture parameters with the van der Waals mixing rules corrected by two temperature-independent binary interaction parameters.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New high-pressure gas–liquid equilibrium data of the system CO2–β-caryophyllene. ► Measurements at 50 and 70 °C, in the pressure range 8.8–15.6 MPa. ► Experimental system: double-chamber gas-phase recirculation apparatus of 340 cm3. ► Both the liquid and the gas phase composition were determined. ► Satisfactory data correlation using the Peng–Robinson equation of state.