Liquid products from Verbascum stalk by supercritical fluid extraction

Verbascum stalk mill was converted to liquid products by using organic solvents, such as methanol, ethanol and acetone, with catalysts (10% NaOH or ZnCl2) and without catalyst in an autoclave at temperatures of 533, 553 and 573 K. The liquid products were extracted by liquid-liquid extraction using benzene and diethyl ether. The yields from supercritical methanol, ethanol and acetone extractions were 44.4, 43.3 and 60.5 wt%, respectively, at 573 K. In the catalytic runs with methanol and ethanol, the extracts were 52.4 and 44.8% using 10% NaOH and 55.5 and 60.6% using ZnCl2, respectively, at 573 K. The yields from supercritical methanol increased from 38.2 to 52.4% as the temperature was increased from 533 to 573 K in the catalytic run. (C) 2000 Elsevier Science Ltd. All rights reserved.