High-pressure phase equilibrium data for systems with carbon dioxide, α-humulene and trans-caryophyllene

The aim of this work is to report phase equilibrium data for the binary systems (CO2 + α-humulene) and (CO2 + trans-caryophyllene), and for the ternary system (CO2 + α-humulene + trans-caryophyllene). Results from literature show that α-humulene and trans-caryophyllene are the main compounds responsible for the anti-inflammatory and anti-allergic characteristics attributed to the medicinal plant Cordia verbenacea D.C., hence giving importance to the phase behaviour investigation performed in this work. Phase equilibrium experiments were performed in a high-pressure, variable-volume view cell over the temperature range of T = (303 to 343) K and pressures up to 20 MPa. (Liquid + liquid) and (vapour + liquid + liquid) equilibrium were observed at T = 303 K, while (vapour + liquid) phase transitions were verified to occur from T = (313 to 343) K, for all systems studied. Thermodynamic modelling was performed using the Peng–Robinson equation of state and the classical quadratic mixing rules, with a satisfactory agreement between experimental and calculated values.