High-pressure phase equilibria and supercritical fluid extraction involving carbon dioxide systems

This dissertation deals with high pressure phase equilibria in systems containing carbon dioxide and with the use of carbon dioxide and carbon dioxide/ethanol mixtures as supercritical solvents in the extraction of taxol from the back of Taxus brevifolia. Vapor - liquid equilibria data were measured for the CO{dollar}sb2{dollar} - 1 hexene, CO{dollar}sb2{dollar} - 1 hexyne, CO{dollar}sb2{dollar} - ethanol, CO{dollar}sb2{dollar} - 1 butanol, and CO{dollar}sb2{dollar} - 1 pentanol systems. These measurements were made due to the interest in CO{dollar}sb2{dollar} - hydrocarbon systems for natural gas and petroleum processing and CO{dollar}sb2{dollar} - alcohol systems as solvent/cosolvent pairs for the extraction of biomaterials. The measurements were made in two apparatuses--a recirculation apparatus and a flow apparatus--designed and developed in this work. The temperatures and pressures for the measurements of the CO{dollar}sb2{dollar} - 1 hexene and CO{dollar}sb2{dollar} - 1 hexyne systems ranged from 308 to 333 K and from 1.63 to 9.35 MPa. The temperatures and pressures for the measurements of the CO{dollar}sb2{dollar} - ethanol, CO{dollar}sb2{dollar} - 1 butanol, and CO{dollar}sb2{dollar} - 1 pentanol ranged from 314 to 337 K and from 4.63 to 11.98 MPa. The data were also correlated with various equations of state.; The other part of this dissertation deals with the extraction of the anticancer drug, taxol. Taxol has been found to be effective in the treatment of ovarian cancer and has also shown promise in the treatment of lung and breast cancer. However, the only current source of taxol is from trees of the Taxus genus. Therefore, the extraction of taxol from ground bark of Taxus brevifolia was studied using supercritical carbon dioxide and carbon dioxide/ethanol mixtures to determine if it could be an effective step in the isolation of taxol. The extractions were performed at 318 K and at pressures ranging from 18.07 to 25.79 MPa. The supercritical fluids were found to extract taxol and were found to be more selective than a conventional liquid ethanol extraction. Taxol compositions in the extracts ranged from 0.27 to 1.82 mass % depending on the pressure, ethanol composition, and history of the extractions.