Depolymerization of Birch-Wood Organosolv Lignin Over Solid Catalysts in Supercritical Ethanol

Abstract

Catalytic depolymerization of birch-wood organosolv lignin was studied in supercritical ethanol at 260 ºC.Three different acid-basic materials namely sepiolite, zeolite ZSM-5 supported on Al 2 O 3 and Sibunit graphite-like mesoporous carbon promoted via oxidation were tested as catalysts.Moreover, Ru-containing catalysts based on these supports were studied.Among the catalysts without ruthenium, Sibunit matherial was found to produce highest yield of liquid products due to the highest amount of surface acid sites. Precipitating Ru significantly increases the activity of all three supports. Using Ru-containingSibunit catalyst in lignin depolymerization process allows to avoid coke formation, increases the amount of aromatic monomers and the total yield of liquid products up to 76 %.The yield obtained in best catalytic experiment is more then twice higher compared to the process without any catalyst.