Renewable materials have been put into the spotlight as the demand for environmentally responsible feedstocks grows yearly. Lignin, an abundant and renewable aromatic polymer, which can source a diverse cast of derivative structures, has yet to rise to the potential it possesses as a material in high technological applications. The expansion of studies and growing interest in its versatility has brought forth materials such as lignin nanoparticles, coatings, films, second generation alcohols, phenolic building blocks for drug synthesis, and many others. Among the many valorization methods thus far pursued, photochemical methods have received relatively low representation, incurring several challenges stemming from less desirable interactions of lignin as a substrate directly with light. As the search for clean, low-emissive processes with high scale-up potential for lignin valorization continued, advances and studies on the benefits and challenges on the use of photochemistry with this class of compounds became the focus of this work.
This thesis will primarily aim to highlight our efforts to find photocatalytic materials and systems to achieve lignin valorization, discuss its limitations and benefits, and provide a pathway towards potential applications of these reactions. Our core values were to find conditions that worked well, but also translating that success into systems that could be greener and less dangerous or environmentally impactful.
We can report to have achieved single-product yields of over 2% in protolignin valorization reactions using Pd and Au based nanoparticles, supported on niobium-based materials. We have also reached up to 2% yields in visible-light reactions using CdSe quantum dots. While literature reports tend to overwhelmingly focus on lignin models, we have kept ours on real lignin, which while more complex and challenging, does present more relevant results in the long run for this field. These results, in addition to molecular model valorization experiments, present a promising prospect for the application of photocatalysis in lignin valorization for the future.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/43857 |
| Date | 28 July 2022 |
| Creators | Matos Pereira Lima, Filipe |
| Contributors | Scaiano, Juan |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Attribution-NonCommercial-NoDerivatives 4.0 International, http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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