(726a) Hydropyrolysis of Lignin and Model Compounds to Ring-Opening Aliphatic Hydrocarbon Biofuels

Among the various biomass conversion technologies being investigated, pyrolysis has been considered as an economic route (i.e., low capital and operating costs) to utilize biomass for bio-fuels and bio-chemicals. However, the produced pyrolysis oils always have higher oxygen content, molecular weight, viscosity and acidity than gasoline and diesel. Further, they are characterized as having thermal instability, corrosiveness, poor volatility, low heating value, high coking tendency and immiscibility with petroleum fuels. Therefore, methods to upgrade the properties of pyrolysis oil is a very challenging topic. Especially, one step thermal conversion of lignin pyrolysis oil to ring-opening aliphatic bio-gasoline appears to be very pragmatic. In this study, an Ir based catalyst was used to upgrade various lignin pyrolysis oil model compounds including, phenol, toluene, xylene, catechol, guaiacol, and syringol. By employing hydrodeoxygenation (HDO) and ring-opening, aliphatic components such as butane, pentane, hexane, heptane, methyl-cyclopentane and cyclohexane etc. have been found as major products (via GC-MS analysis). To further investigate the mechanism, deuterium gas was used to trace the HDO and ring-opening process. By using various NMR analysis methods to detect deuterium atoms, several mechanisms have been proposed. To compare with the Ir, Ni based catalyst have also been investigated in this study. Finally, real lignin pyrolysis oil has been examined and upgrading products have been characterized by GC-MS and NMR.