Hydrolysis/dehydration/aldol-condensation/hydrogenation of lignocellulosic biomass and biomass-derived carbohydrates in the presence of Pd/WO3-ZrO2 in a single reactor

Hydrolysis/dehydration/aldol-condensation/hydrogenation of lignocellulosic-biomass (corncobs) and biomass-derived carbohydrates (tapioca flour) to produce water-soluble C-5-C-15 compounds was developed in a single reactor system. WO3-ZrO2 efficiently catalyzed the hydrolysis/dehydration of these feedstocks to 5-hydroxymethylfurfural and furfural, while the impregnation of WO3-ZrO2 with Pd allowed sequential aldolcondensation/hydrogenation of these furans to C-5-C-15 compounds. The highest C-5-C-15 yields of 14.8-20.3% were observed at a hydrolysis/dehydration temperature of 573 K for 5 min, an aldol-condensation temperature of 353 K for 30 h, and a hydrogenation temperature of 393 K for 6 h. The C-5-C-15 yield from tapioca flour was higher than that from corncobs (20.3% compared to 14.8%). Tapioca flour produced more C-6/C-9/C-15, whereas corncobs generated more C-5/C-8/C-13 compounds due to the presence of hemicellulose in the corncobs. These water-soluble organic compounds can be further converted to liquid alkanes with high cetane numbers for replacing diesel fuel in transportation applications. (C) 2010 Elsevier Ltd. All rights reserved.