Thujopsene

Abstract: The extraction of cedarwood oil (CWO) using supercritical carbon dioxide (SC-CO2) has been investigated with respect to the effects of extraction temperature and pressure, length of extraction, and age of cedarwood chips. Steam distilled and SC-CO2 derived CWOs were compared by gas chromatography and sensory evaluation. The extraction of CWO increased with extraction temperature, except at the lowest pressure utilised. The highest percentage contribution of thujopsene to the SC-CO2 derived CWO occurred with the combination of 1500 psi and 70°C or 100°C. Essentially all of the CWO was extracted from the wood matrix in the first 10 min, however, complete extraction of water required ca. 25 min. The amount of CWO extracted decreased with increasing age of the cedarwood chips. This decrease was greatest for the more volatile hydrocarbon components, thujopsene and cedrene. The mean weight percentage yields of CWO for steam distillation and SC-CO2 extraction were 1.3 and 4.4%, respectively. An experienced analytical sensory panel selected the SC-CO2 derived CWO as being more similar to the original cedarwood chips than the steam distilled CWO. Volatile collections performed on SC-CO2 extracted, steam distilled and unextracted cedarwood chips indicated that the SC-CO2 extracted chips released almost no volatiles, whereas the unextracted chips released a higher amount of volatiles. The steam distilled cedarwood chips released an intermediate level of volatiles. Copyright © 2000 John Wiley & Sons, Ltd.

Abstract: Three new advanced biofuels have been produced from sesquiterpene feedstocks. Cedarwood oil, which is primarily composed of the sesquiterpenes thujopsene, α-cedrene, and β-cedrene, was hydrogenated to generate a fuel blend (HCWO) with a cetane number of 31 and a volumetric net heat of combustion (NHOC) more than 12% higher than conventional jet fuel. Hydrogenation under pressures ranging from 400 to 440 psi allowed for reduction of the double bond in thujopsene while keeping the cyclopropane ring intact. A single component high density fuel containing only hydrogenated α-cedrene (cedrane) was then prepared by dehydration and hydrogenation of α-cedrol, and found to have an even higher NHOC and lower viscosity than HCWO. Cedrane was then isomerized to 1-ethyl-3,5,7-trimethyladamantane (ETMA) and a mixture of other alkyl adamantanes. The adamantane mixture had a cetane number of 46 and a viscosity suitable for use in a conventional diesel engine. This work shows that sustainable multicyclic sesquiterpenes are versatile feedstocks to ultra-performance fuels that combine high densities with high cetane numbers.

Abstract: The 11 taxa of Juniperus with widespread distribution in the United States and with significant biomass production were investigated to determine their yields of cedarwood oil and the major components of commercial interest: alpha-cedrene, beta-cedrene, thujopsene, cuparene, cedrol, and widdrol. Taxa examined wereJ. ashei, J. californica, J. erythrocarpa, J. deppeana, J. monosperma, J. occidentalis var.occidentalis, J. o. var.australis, J. osteosperma, J. pinchotii, J. scopulorum, andJ. virginiana. The volatile heartwood oils were removed by steam distillation and analyzed by gas chromatography-mass spectroscopy to determine their yields and composition. Cedarwood oil yields inJ. erythrocarpa andJ. scopulorum were comparable to those of the two species currently being utilized (J. ashei, J. virginiana).