Repurposing of environmentally damaging fluorinated gases and polymers
File(s)
Author(s)
Sheldon, Daniel
Type
Thesis
Abstract
Fluorinated gases (F-gases) and perfluoroalkyl substances (PFAS) have a widespread global use in industries such as refrigeration and electrical insulation, largely due to their unique chemical and physical inertness. They are often treated as ‘single-use’, and due to a lack of methods for recycling or repurposing, they have become pervasive in our environment.
F-gases are potent greenhouse gases and create a significant contribution to global warming, while human exposure to PFAS is linked to a range of serious health issues. Thermal destruction methods for these molecules are extremely energy intensive and often lead to toxic by-products. There is a great opportunity to tackle the environmental and sustainability issues created by waste F-gases and PFAS by developing chemical reactions that break apart these molecules, despite their extreme lack of reactivity. This approach could prevent the release of F-gases and PFAS to the environment, while also providing a pathway to repurpose the valuable fluorine content into building blocks for the synthesis of new fluorinated molecules. Fluorine is regularly incorporated into pharmaceuticals and agrochemicals, and there is a growing demand for new reagents and building blocks for the installation of fluorinated groups in complex molecule synthesis.
In this thesis, we demonstrate new reactions to repurpose environmentally damaging F-gases and PFAS using reactive main group compounds. We have studied the mechanism behind these reactions, allowing us to advance the understanding of the fundamental chemistry of these molecules and methods for their activation. We have also demonstrated the use of the reaction products as fluorinated building blocks in onwards synthesis.
F-gases are potent greenhouse gases and create a significant contribution to global warming, while human exposure to PFAS is linked to a range of serious health issues. Thermal destruction methods for these molecules are extremely energy intensive and often lead to toxic by-products. There is a great opportunity to tackle the environmental and sustainability issues created by waste F-gases and PFAS by developing chemical reactions that break apart these molecules, despite their extreme lack of reactivity. This approach could prevent the release of F-gases and PFAS to the environment, while also providing a pathway to repurpose the valuable fluorine content into building blocks for the synthesis of new fluorinated molecules. Fluorine is regularly incorporated into pharmaceuticals and agrochemicals, and there is a growing demand for new reagents and building blocks for the installation of fluorinated groups in complex molecule synthesis.
In this thesis, we demonstrate new reactions to repurpose environmentally damaging F-gases and PFAS using reactive main group compounds. We have studied the mechanism behind these reactions, allowing us to advance the understanding of the fundamental chemistry of these molecules and methods for their activation. We have also demonstrated the use of the reaction products as fluorinated building blocks in onwards synthesis.
Version
Open Access
Date Issued
2023-03-23
Date Awarded
01/08/2023
License URL
Advisor
Crimmin, Mark
Sponsor
Engineering and Physical Sciences Research Council
Publisher Department
Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)