Milled Onopordum heteracanthum stalks were converted to liquid products in organic solvents (methanol, ethanol and acetone) with (KOH and ZnCl2) and without catalyst in an autoclave at temperatures of 523, 543 and 563 K. Effects of liquefaction parameters such as catalyst and solvent were investigated. The percentage yields from supercritical methanol, ethanol and acetone conversions were 48.2, 50.4 and 66.2 at 563 K in the non-catalytic runs, respectively. In the catalytic run with ZnCl2, the highest conversion (70.2%) was obtained in acetone at the same temperature. The obtained liquid products at 563 K were analyzed and characterized by elemental, Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry. 106 different compounds have been identified by GC-MS in the liquid products obtained in methanol at 563 K. (C) 2014 Elsevier Ltd. All rights reserved.