Date of Award
Doctor of Philosophy (PhD)
This thesis describes research under the rubric of the Center for Sustainable Polymers that is aimed at two separate goals. The goal of the first project (Chapters 1 and 2) was to develop a deeper mechanistic understanding of a method for the synthesis of linear α-olefins, while the second aimed at synthesizing statistical copolymers that incorporate olefin-containing monomers through ring-opening transesterification polymerization and showing that these copolymers could be functionalized. In Chapter 1, published methods for the conversion of fatty acids to linear α-olefins are reviewed to provide context for the mechanistic work we accomplished (Chapter 2). In Chapter 2 the dehydrative decarbonylation mechanism is investigated with the hopes of identifying factors that may lead to better catalyst design. A series of Pd-acyl complexes were synthesized with hydrocinnamoyl chloride and phosphine ligands. The three different ligands (PtBu3, PPh3, and dppe) were chosen for their ability to induce differing coordination environments around Pd to examine what role the steric environment has specifically on the decarbonylation and β-hydride elimination steps. Experimental work was informed by theory to better understand the various thermodynamic differences between ligands and upon chloride abstraction from Pd. A reactivity trend, as determined by the formation of styrene, was observed in the order of PtBu3 > dppe > PPh3. Key findings include: the β-hydride elimination step has the highest impact from ligand choice, the low coordination number induced by PtBu3 lowers reaction barriers for all steps of the catalytic cycle and the trans coordination of the Pd complex with two PPh3 ligands contributes to a low efficiency for styrene production. In Chapter 3, a series of olefin-containing caprolactone monomers were statistically copolymerized with racemic-lactide to create a new class of copolymers. The new copolymers, bearing uniformly distributed pendant olefins, underwent a series of post-polymerization modification reactions to convert the alkenes into numerous functionalities such as hydroxyl, bromo and epoxide units. Furthermore, small, and large molecules, such as 1-octanethiol, polyethylene glycol, polycaprolactone, polydimethylsiloxane and polymethacrylate were fused with the copolymers through grafting-to and grafting-from reactions by thiol-ene, metathesis, ring-opening polymerization and free radical polymerization reactions.
Chair and Committee
William B Tolman
Wiessner, Tedd Casey, "Toward Enhancing the Synthesis of Renewable Polymers: Feedstock Conversions and Functionalizable Copolymers" (2022). Arts & Sciences Electronic Theses and Dissertations. 2785.