Date of Award

Spring 5-5-2023

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Chemical Engineering

Advisor

Thomas J. Schwartz

Second Committee Member

M. Clayton Wheeler

Third Committee Member

William J. Desisto

Additional Committee Members

Adriaan Van Heiningen

Francois Amar

Abstract

Concerns around climate change and the use of fossil resources contributing to increasing carbon dioxide concentrations in the atmosphere has motivated transitions to use biomass resources for the production of specialty chemicals and fuels, in hopes of creating a more cyclical use of carbon. The work presented here focuses on two different aspects of catalytic upgrading of biomass-derived platform molecules using heterogeneous acid catalysts. First, we use an interdisciplinary and iterative approach to process development for producing a diesel fuel additive from pyrolysis oils of woody biomass. We use fuel property calculations to define measures of success in chemical upgrading processes of hydrogenation and dehydration to decrease the oxygen content of pyrolysis oil and produce a stable fuel additive consisting of ethers and hydrocarbons that encourage complete combustion. We then explored reaction conditions for producing the best fuel additive from woody biomass pyrolysis oil. We were able to produce a blendstock that meets DOE goals for fuel properties, and an upgrading process has been selected for scale up.

Second, we explore the concept of solvation and condensed phase heterogeneous catalyzed dehydration reactions. Small batch reactors were used to study esterification rates of model compounds butanol and butyric acid in the presence of two different liquid solvents. Toluene was used as a nonpolar solvent, and tetrahydrofuran (THF) was used as a polar aprotic solvent. Experimental data showed that reaction rates are different in order of magnitude as well as reaction order with respect to both reactants in the two different solvents. Computational studies using density functional theory (DFT) calculations were then used to propose a reaction mechanism and fit rate constants and equilibrium constants to the experimental data. We then describe the concepts utilized for this work that are applicable to condensed phase studies but are not mainstream considerations for traditional catalysis studies.

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