Effects of catalysts and solvents on liquefaction of Onopordum heteracanthum for production of bio-oils

•Onopordum heteracanthum stalks were converted to liquid and gas products.•Acetone as solvent and zinc chloride as catalyst provide the optimum conditions for liquefaction.•The liquefaction process depends on temperature, solvent and catalyst.•106 different compounds were identified by GC–MS in the liquid products obtained in methanol at 563K. 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 563K. 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 563K 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 563K 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 563K.