From glucose to γ-valerolactone: development of novel catalytic methodologies

The body of work presented in this thesis focuses on the conversion pathway from glucose to γ-valerolactone (GVL). GVL has been identified as a potential fuel additive, and the developments in this thesis contribute towards making it a more sustainable process. There are two results chapters in this thesis, chapter 3 and 4s; the first one explores the dehydration of glucose to methyl levulinate. A range of solid acid catalysts was evaluated. Efforts were taken to limit the polymerisation side reaction by changing reaction conditions and introducing methanol as a solvent, as opposed to the typically used water. It was found that the polymerisation greatly depends on the concentration of substrate. Reducing the polymerisation is crucial, as they not only reduce the carbon balance, but adsorb on the catalyst surface, reducing re-usability. The second results chapter tackles the hydrogenation of levulinic acid to γ-valerolactone with the use of Cu-ZrO2 catalysts. A novel catalyst preparation method was developed which allowed to reduce the copper loading from 50% mol. to 30% while retaining high activity. The surface species were investigated and it was found that well-dispersed copper particles with strong metal-support interactions are the most active for this reaction. Steps were taken to maximise the number of those sites, such as optimising the reduction conditions and acid washing the labile copper off the surface. Mechanistic studies were also carried out to prove that H2O from the solvent is critically involved in the hydrogenation mechanism