(677e) Selective Upgrading of Lignin Dimers to Aliphatic Hydrocarbon Biofuels

Due to the growing concerns about the effects of carbon dioxide emissions from fossil fuels, there has been a growing focus on developing sustainable energy sources, such as biomass. However, as one of the promising platforms – biomass thermal conversion processes produce biofuel precursors, which have various challenging properties, including higher oxygen content, molecular weight, viscosity and acidity than gasoline and diesel, and consequently they are characterized as having thermal instability, corrosiveness, poor volatility, low heating value, high coking tendency and immiscible with petroleum fuels. Over the last few decades, the catalytic upgrading processes including hydrogenation (HYD) and hydrodeoxygenation (HDO) that have traditionally used for converting petroleum fuels are being applied to biomass upgrading. In this study, the use of noble metals, including platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), and iridium(Ir) etc. as catalysts for upgrading of lignin model dimmers (beta-O-4, 5-5, 4-O-5, beta-5 etc,) have been examined. By employing isotopic tracing and NMR in-situ monitoring, several possible mechanisms have been proposed. The proposed intermediates and reaction pathways were further evaluated by computational calculation.