(207e) Investigation of Benzofuran Deoxygenation In Sub and Supercritical Water

Algae have received much attention as a biomass source for second-generation biofuels.  The dilute solutions of water that algae grow in provide significant fuel processing challenges.  One proposed solution is to process algae in the aqueous phase through hydrothermal liquefaction, to remove the energy intensive drying step.  Hydrothermal liquefaction produces a crude bio-oil high in nitrogen and oxygen content.  The high oxygen content is likely due to the presence of phenolic and cyclic oxygen-containing compounds.  Benzofuran was chosen as a model cyclic oxygen-containing compound.

Our work focuses on the deoxygenation of benzofuran over Pt/C in supercritical water.  The effects of hydrogen pressurization, water density, residence time, and reaction temperature were examined.  The deoxygenation reaction is highly dependent on amount of hydrogen added to the reactor, but shows little effect when the water concentration is varied.  The primary product benzofuran deoxygenation is ethylbenzene.  Smaller amounts of benzene and toluene with the accompanying ethane and methane were also observed.  Fully hydrogenated products such as straight chain or cyclic alkanes were observed only in minute quantities.  The results of the kinetic model will also be discussed.