Path to Predict the Vapor Pressure and Enthalpy of Vaporization of the Components in Essential Oils

Essential oils contain terpenes and volatile compounds which are widely used in flavor and fragrance, cosmetic and medicine industries. Fractionation of essential oils separate these compounds and modelling and simulation plays a key role in optimizing the fractionation processes. The success of modelling and simulation of fractionating the essential oils heavily depends on the accurate prediction of vapor pressure and enthalpy of vaporization. This study examined the applicability and reliability of predictive methods for estimating the vapor pressure and enthalpy of vaporization of essential oils. Ten compounds were selected as case study, based on the export market for essential oils in Sri Lanka. Antoine method was found to give accurate and reliable data for all the ten compounds. But the use of Antoine method is limited due to unavailability of Antoine coefficients for most of the essential oil compounds over a wider range of temperatures. The selection of the suitable corresponding states group contribution method was found to depend on the type of compound and the range of operating temperatures. Based on the results of this study, the path to select the most suitable predictive method for a given essential oil compound with the applicable range of temperatures is recommended.