Date of Award

Fall 12-18-2020

Level of Access

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

Carl P. Tripp

Caitlin Howell

Abstract

This dissertation involves several hydrogenolysis reactions but is mainly focused on hydrodechlorination (HDC) of chlorobenzene (PhCl) and hydrodeoxygenation (HDO) of 2-furancarboxylic acid (FCA). Hydrodechlorination of PhCl has been the subject of research for some time. Here, we used a Pd/C catalyst to study this reaction though rigorous kinetics and mechanistic analyses in a CSTR reactor. The H2/D2 kinetic isotope effect (KIE) experiment revealed that H2 is not involved in a rate controlling step. The kinetics data are in agreement with similar systems reported before and follow a first-order dependence on chlorobenzene, half order for hydrogen and an inverse first order with respect to HCl. These data suggest a mechanism that involves C-Cl cleavage in the rate controlling step preceded by adsorption of reactant and followed by desorption of products from the surface. The derived rate expression was used in a microkinetic model to predict the observed rates of this reaction. This model successfully captures the experimental trends observed in the kinetic studies. Moreover, motivated by the applications of in situ spectroscopic techniques, the detailed design of an FTIR cell which enables both steady state and transient studies to measure kinetics and investigate the mechanism of reactions at a molecular level, is included.

Hydrodeoxygenation of 2-furancarboxylic acid was investigated to produce delta-valerolactone, which represents a series of functionalized lactone molecules that have a potential to be used in prospective polymers. Motivated by excellent HDO activity reported for Ru/TiO2 catalysts, and with the aim of taking advantage of the built-in bifunctionality of this catalyst when introduced to hydrogen, we have used Ru/TiO2 toquantitatively synthesize the functionalized lactone monomer (FDHL). The focus of our work has been to optimize process parameters, including temperature, solvent, catalyst support, metal loading, weight of the catalyst and reaction time, to achieve an acceptable yield for the target product. The yield of 53% to -hexalactone (DHL) for a simple 5-methyl-2-furancarboxylic acid was significantly greater than the previous reports.

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