This work aims to provide a detailed study of the solid Lewis acid catalyst, Sn-Beta, and particularly focuses on its use as a catalyst for biomass valorisation. Particular emphasis is put on identifying several criteria that are necessary for evaluating the feasibility of the material for intensified operation during the continuous conversion of biomass, such as stability and productivity. The catalyst is tested in continuous flow apparatus for some relevant biomass reactions, such as the valorisation of furfural, and the isomerisation of glucose to fructose. Investigation of the deactivation mechanisms is done by combining kinetic data and characterisation of the material, both fresh and used, in order to relate spectroscopic evidence to catalytic performance. The understanding of deactivation is used to develop countermeasures in order to prevent or mitigate the undesired phenomenon. Important parts of the work are also focused on material synthesis and optimisation, and combinations of different catalysts are also explored, in order to improve the overall performance of the catalytic systems studied within the work. This thesis begins with a detailed study of the effect of metal loading on the intrinsic activity of Sn-Beta (Chapter 3), where a combination of kinetic experiments and characterisation techniques are presented. This permits identification of the most suitable catalyst for continuous flow catalysis. Continuous flow experiments are then carried out in order to probe the deactivation of the catalyst. A first study of the continuous performance of Sn- Beta focuses on the model reaction of the transfer hydrogenation of cyclohexanone to cyclohexanol (Chapter 4). Following this, the transfer hydrogenation of a more complex system is studied. Particularly, the cascade conversion of furfural to 2-(butoxymethyl) furan, through tandem transfer hydrogenation and etherification over bifunctional Sn-Beta catalysts, is studied (Chapter 5). Having identified the promising stability properties of Sn-Beta during organic phase reactions, the reported “water tolerance” of Sn-Beta is then probed during the continuous isomerisation of glucose to fructose (Chapter 6). Despite showing poor levels of activity and stability in bulk water solvent, excellent continuous performance is observed when solutions of methanol containing small amounts of water (1 – 10 wt. %) are employed. In closing (Chapter 7), the consequences of the findings of this research, in addition to the pertaining challenges these findings open, are also considered.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:753576 |
| Date | January 2018 |
| Creators | Padovan, Daniele |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/113811/ |
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