Due to the inevitable depletion of fossil fuel reserves, the development and utilization of renewable resources carry tremendous strategic significance in sustaining society's ever-growing needs for energy and materials in the long run. Amongst all forms of renewable energy resources, biomass assumes the unique position of being the only renewable source of carbon, from which liquid transportation fuels and organic chemicals are produced. The present thesis studies the catalytic conversion of key oxygenated platform molecules derived from the cellulose fraction of lignocellulosic biomass using solid acid catalysts to produce hydrocarbon fuels and commodity chemicals.;A catalytic route was first developed to convert an aqueous stream of gamma-valerolactone (GVL) over two solid acid catalysts into liquid alkenes with potential application as jet or diesel fuel precursors. In this process, GVL was nearly quantitatively decarboxylated into a stream of butene, which allowed for the use of well-established olefin oligomerization chemistry to produce C8+ hydrocarbons with overall yields over 60%. Kinetic studies on the inter-conversion between GVL and pentenoic acids and their decarboxylation led to the development of a computerized model that satisfactorily captures experimental trends and thus can serve as a useful tool in reactor design and process optimization.;Experimental evidences obtained at short space times revealed that 1-butene was the primary decarboyxlation product. Based on this observation, solid Lewis acid catalysts were used to achieve selective production of 1-butene via GVL decarboxylation by effectively suppressing isomerization of the terminal olefin.;Alternatively, GVL was converted into pentanoic acid by consecutive ring opening and hydrogenation over a bifunctional palladium-niobia catalyst. Pentanoic acid was further upgraded via ketonization reaction to form nonanone for use as diesel precursors. Therein, commercial niobia was found to crystallize and lose its surface area under hydrothermal conditions. Two niobia-silica composite materials were synthesized which showed significant improvement in hydrothermal stability.;Finally, a highly selective process was developed to convert furanics, including 2,5-dimethylfuran, 2-methylfuran and furan into p-xylene, toluene and benzene, respectively, through Diels-Alder type cycloaddition with ethylene followed by dehydration. Tungstated zirconia was identified as a highly efficient catalyst for this reaction due to its high Brønsted acidity.
展开▼
