ABSTRACT: Solubility of essential Oils in Liquid and Supercritical CO2

AUTHOR: Odell L. Glenn Jr.

KEYWORDS: Supercritical fluids; solubility; phase equilibrium; essential oils

In order to deliver essential oils dissolved in CO2, the solubility of the given oil must be known as a function of temperature and pressure. The objective of this study is to measure the solubility of three oils in supercritical CO2. Although there are some data on the solubility of essential oils in supercritical CO2 there are no known data available on the solubility of tea tree oil, cedar wood oil and hinoki oil at any temperature or pressure in either liquid or supercritical CO2. These oils were selected because of the potential utility as acaricides in the home environment. These oils are each a mixture of several chemical species, which greatly complicates the measurement of solubility. To address this, gas chromatography/mass spectrometry has been employed to identify the major component on each oil. In formulating a mathematical model to predict and estimate the phase behavior of each binary system, the PREOS have been employed. The PREOS is preferred for predicting liquid densities, especially for non- polar materials, as well as for reasonable accuracy near the critical point. The interaction parameter for binary mixing, kij has been computed through MATLAB and as well as the solubility over a range of temperatures and pressures. Experimental data will be determined through the use of the dynamic flow method from an extractor. Temperatures will be from 25°C to 70°C and pressures from 6.8 MPa to 20.7
MPa.