Supercritical Methanol Depolymerization and Hydrodeoxygenation of Maple Wood and Biomass-Derived Oxygenates into Renewable Alcohols in a Continuous Flow Reactor

Supercritical methanol depolymerization and hydrodeoxygenation (SCM-DHDO) of biomass is a technology to produce C2–C9 alcohols in a single reaction step. Previous research has shown that this technology is effective in batch reactors but produces large amounts of undesired CO and H2 gas from the reforming of the methanol that make the process economically infeasible. In this work, we show that methanol reforming can be minimized to provide the stoichiometric amount of H2 required for hydrodeoxygenation by recycling the product gases. We also show that methanol can be synthesized during the SCM-DHDO process with a sufficient cofeed of CO and H2. In addition, we demonstrate that the catalyst is stable for more than 100 h time on stream in a continuous packed bed reactor using glycerol as a model feedstock. The alcohol yields from glycerol in the fixed bed exceeded yields from batch reactions. In a single pass system, the conversion of cellulose and maple wood to alcohols was obtained by first solubilizing in methanol and then converting to monoalcohols over a fixed bed of catalyst.