The purpose of this work is to investigate the use of catalytic systems for the production of fine and value-added chemicals from lignin. Lignin is the second most abundant polymer on earth after cellulose and comprises the greatest amount of aromatic functionalities in nature. The overall structure of lignin is so vast and largely unknown that small compounds which are fashioned on some of the bonding patterns within lignin are employed to study how these bonding patterns would react under a given set of conditions. The over-arching theme within is the use of model compounds which have been synthesised with a view to having the linkages present within native lignin. Lignin model compounds which have been synthesised include the key linkages which can be classified as ether or C-C bonds and have been characterised by NMR, MS, LC-MS and HPLC. Following implementation of synthetic routes towards these target compounds, enzymatic and photocatalytic systems were employed to study routes of degradation and determine if there is any resistance of bonds present within. Routes of oxidative degradation which have been reported within for the photocatalytic consumption of the model compounds have been discussed and rationalised along with possible mechanisms for the enzymatic consumption of said model compounds. Alongside the methods of catalytic valorisation of the lignin model compounds, herein is described, in detail the synthetic routes towards a new class of compound- a biomass model compound. These new model compounds are fashioned on some of the pieces of biomass which have been previously extracted and are found as ‘lignin-carbohydrate complexes’, these complexes have specific bonding patterns, attempts to recreate these linkages are described with some success. The significance of these new models will allow the study in a 100% aqueous solution pushing evermore towards the Green Chemistry goals.
Date of Award | Jul 2023 |
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Original language | English |
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Awarding Institution | - Queen's University Belfast
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Sponsors | Engineering & Physical Sciences Research Council |
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Supervisor | Gary Sheldrake (Supervisor) & Peter Knipe (Supervisor) |
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- Sustainability
- lignin
- biomass
Synthesis and catalytic valorisation of advanced biomass model compounds
Murnaghan, C. W. J. (Author). Jul 2023
Student thesis: Doctoral Thesis › Doctor of Philosophy