New Catalysts for Advanced Biofuels Synthesis and Cooperative Catalysis

Abstract

This thesis investigates the catalytic upgrading of lower alcohols, such as ethanol and methanol, into higher-value alcohols through the Guerbet reaction, focusing on the production of isobutanol. The Guerbet reaction offers significant potential for sustainable biofuel synthesis, and this work addresses key aspects of catalyst design, ligand effects, and reaction condition optimisation. Key advances are presented in using monodentate phosphine ligands with ruthenium catalysts, achieving high yields and selectivity for isobutanol production. The electronic and steric properties of ligands were systematically analysed, demonstrating the importance of balancing these effects to stabilise reactive intermediates and minimise undesirable side reactions. A detailed study of cone angles and electronic parameters provides valuable guidance for optimising ligand design and catalytic performance. The work also highlights the promising role of 1,1'-bis(diphenylphosphino)ferrocene (dppf) ligands in enhancing catalytic activity. Combining ruthenium catalysts with dppf significantly improved the upgrading of ethanol and methanol, resulting in higher yields and improved selectivity. These findings underline the potential of bidentate ligands to advance biofuel catalysis and bridge the gap between academic research and industrial applications. Additionally, the thesis explores the synthesis and characterisation of Frustrated Lewis Pair (FLP) systems as a novel contribution to catalytic research. Palladium-based FLPs were successfully synthesised, offering new insights into their structural and electronic properties. While this study did not evaluate their catalytic performance, these systems lay the groundwork for future research into hydrogen activation and alcohol upgrading applications. This thesis contributes to the broader understanding of homogeneous catalysis and its role in sustainable energy solutions by addressing challenges in catalytic efficiency, selectivity, and stability. The findings provide a foundation for advancing isobutanol production and support the development of greener biofuel technologies.