Phase equilibrium engineering of jojoba oil extraction with mixed-CO2 + propane solvent

Jojoba oil is an important ingredient of many cosmetic and hair care products, which is composed of high-molecular weight monounsaturated esters. It is a liquid wax extracted from the seeds of Jojoba plant (Simmondsia chinensis) by mechanical pressing, followed by hexane extraction of the pre-pressed jojoba meal. Health and environmental concerns associated with the use of solvents like hexane have placed new demands on the cosmetic and pharmaceutical industry to invest in clean technologies such as Supercritical Fluid Extraction. Jojoba oil is partially miscible with CO2 in the liquid and supercritical states. On the other hand, liquid propane has better solvent characteristics, since it shows complete miscibility with jojoba oil below 343 K. The main drawback of propane is its flammability; any percentage of it in a propane/air mixture above 2.15 vol.% will be enough to burn the propane. However, a 30 vol.% of CO2 in the vapor phase can be used to turn the mixture propane/CO2/air non-flammable. In this work, the phase equilibrium engineering of jojoba oil extraction with mixed-CO2 + propane solvents has been carried out in order to select appropriate operating conditions.