Author: Daniel    McKeon

Major: Chemical Engineering

Graduation Year: 2022

Thesis Advisor: Thomas J. Schwartz

Description of Publication: Growing concerns around climate have piqued interest in using biobased alternatives in place of fuels and chemicals traditionally made from petroleum. Lignocellulosic biomass has been noted for its potential as a biobased chemical precursor in the context of a biorefinery. It can be pyrolyzed to yield an oil, but catalytic upgrading is required to lower oxygen content to suitable levels. Ruthenium supported on titania has been identified as a catalyst suitable for hydrodeoxygenation of oxygenated aromatic pyrolysis products in the liquid phase. In liquid phase reactions, intermolecular attractions between the solvent and the reactants can significantly change chemical activities and thus reaction rates. This thesis investigates solvent effects on the hydrogenation rate of phenol over ruthenium supported on titania. Use of a model compound allows detailed kinetics studies to be performed which help gather insight into the more complex kinetics of biomass reactions. Phenol is chosen as a model compound for lignocellulosic biomass hydrodeoxygenation, as it has shown the most resistance to deoxygenation. This work investigates phenol hydrogenation in various solvents and identifies a significant solvent effect that can be attributed to differences in activity coefficients in the desorption of the first product in the hydrogenation reaction of phenol. The trend of rate effects from solvents is not obvious, with 1-butanol and isopropanol producing significantly different rates, and no trend with polarity is observed across the solvents. This warrants the use of transition state theory expressions to sufficiently analyze the phenomena observed.

Location of Publication:

URL to Thesis: https://digitalcommons.library.umaine.edu/honors/763