| The high water solubility of biomass derived carbohydrates and the inherent removal of hydroxyl groups to form water require water tolerant solid acids catalysts for processing. From an initial screening in high water environments, three amorphous candidates emerged: silica alumina, niobium phosphate and niobic acid. The effect of sweep gas showed a strong influence on the rate of dehydration due to the sparging of water through the reactor. Above a critical value all the water can be sparged, suggesting operation at low gas flow rates to avoid full water evaporation from non volatile carbohydrates.;High yields of alkanes (C6 or C7-C15) can be produced via aqueous phase dehydration and hydrogenation (APDH) from sorbitol or from adducts produced in a multistep process using a variety of biomass-derived chemicals. The overall carbon yield from fructose to C 7-C15 is 58-69% for HMF-acetone systems, while the overall carbon yield from various furfurals to C7-C15 species is 79-94%, with the product distribution determined by the choice of reagents in the aldol condensation step. HMF degradation is base catalyzed with the resulting acidic degradation products neutralizing the base catalyst thus limiting this approach. In APDH, a decrease in the gas sweep and an increase in feed water content greatly increased the carbon balance and reactivity. Additionally, niobium-based catalysts demonstrated superior reactivity in comparison to a silica-alumina based catalyst, with the higher reactivity attributed to the coordination environment of the niobium acid center.;Glucose and sorbitol reactions over a Pt/Re on C catalyst produced four major classes of chemicals, namely ketones, alcohols, acids and heterocyclics in one step. These monofunctional species can be upgrading to liquid fuels through various C-C coupling reactions, namely oligomerization, aromatization, ketonization and aldol condensation and finally finished by dehydration/hydrogenation of the resulting adducts.;Investigations into the production of chemicals from biomass derived carbohydrates showed that lactic acid and methyl lactate can be produced from triose sugars over Lewis acid catalysts. Lastly the thermodynamics and kinetics of chemicals derived from levulinic acid were investigated, with niobic acid demonstrating around an order of a magnitude higher reactivity than silica alumina. |
