JOURNAL OF SUPERCRITICAL FLUIDS, vol.95, pp.298-317, 2014 (SCI-Expanded)
Cirsium yildizianum stalks were liquefied in organic solvents under supercritical conditions with and without catalyst in a cylindrical reactor at temperatures of 260, 280 and 300 degrees C. The effects of liquefaction temperature, catalyst type and solvent on product yields were investigated. The liquid products (bio-oils) were extracted with diethyl ether and benzene using an extraction procedure. The liquid yields in supercritical methanol, ethanol and acetone were found to as 45.66%, 49.34% and 60.05% in the non-catalytical runs at 300 degrees C, respectively The highest conversion (liquid + gaseous products) was obtained in acetone with 10% ferric chloride at 300 degrees C in the catalytic runs. The produced liquids at 300 degrees C were analyzed and characterized by elemental, GC-MS and FT-IR. 85,79 and 60 different types of compounds were identified by GC-MS obtained in methanol, ethanol and acetone, respectively. The liquid products were composed of various organics including aromatics, nitrogenated and oxygenated compounds. (C) 2014 Elsevier B.V. All rights reserved.