(396d) Heterogeneously Catalyzed Conversion of Cellulose to Sugar Alcohols

As fossil fuels become more economically, politically and environmentally problematic, biomass-derived fuels are attractive potential replacements. In order to avoid negatively impacting food supplies, lignocellulosic biomass is specifically sought after as an energy/chemical resource. A major challenge of utilizing this resource is the development of liquid-phase catalytic processing so as to enable large-scale production. Heterogeneously catalyzed processes, much like that used in the petroleum industry, would enable refinery-like operation and offer the potential to avoid disadvantages of current techniques (i.e. liquid acid hydrolysis, enzymes).

With this in mind, supported metal catalysts were investigated for hydrolysis/hydrogenation of cellulose. Both microcrystalline cellulose and lignocellulosic biomass (algal residue) were subjected to catalytic treatment in an H2 pressurized batch reactor. In each case, samples were taken at different times to monitor the formation of sorbitol, a possible platform chemical for aqueous phase reforming to liquid alkanes. The effect of temperature and substrate concentration were investigated; however, different behaviors were exhibited for each reactant. The samples were characterized via HPLC and compared with known standards for component identification and quantitation.

In addition to optimizing conversion, it is essential to understand the fundamentals of the underlying reactions. Key considerations are the role of catalyst acidity and stability in the aqueous environment, as well as the interaction between the two solid counterparts.