Date of Award


Document Type

Open Access Dissertation


Chemical Engineering

First Advisor

Andreas Heyden


With worldwide fossil fuel resources dwindling and greenhouse gas emissions rising, it is urgent to find renewable liquid fuel alternatives from e.g. biomass to meet the world’s growing energy demand. Lipid feedstocks and pyrolysis oils from woody biomass can be utilized for the production of second-generation biofuels via a catalytic hydrodeoxygenation (HDO) process. The conversion of fatty acids and esters plays an important role in the activity and selectivity of these processes. Understanding the HDO reaction mechanism of organic acids and esters on metal surfaces is a prerequisite for the rational design of new HDO catalysts specifically designed for upgrading pyrolysis oils or lipid feedstocks. We theoretically studied the HDO of propionic acid and methyl propionate, our model acid and ester molecules, on flat and step metal surfaces in the absence and presence of solvents. Our theoretical results suggest that the activity of palladium flat and step surfaces are very similar under typical reaction conditions. Decarbonylation was identified to be the dominant mechanism, and in our sensitivity analysis, CH3CH2CO-OH bond dissociation as well as dehydrogenation of the α-carbon were found to be the most rate-controlling steps in all reaction media. Finally, with the help of an experimental kinetic isotope study on propionic acid, we confirmed the results of our sensitivity analysis.