Electroorganic chemistry as a green synthesis methodology

Seitz, Jakob 2022. Electroorganic chemistry as a green synthesis methodology. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

In recent years, the field of green chemistry has grown in importance as chemical processes are also evaluated on their environmental impact and the sustainability. This demand for green synthetic methodologies has been addressed with a variety of enabling technologies, such as mechanochemistry, photochemistry or electrochemistry. In this work, the focus will be on contributions of electroorganic synthesis towards green chemistry. In the first part of this work, the development of chiral electrodes for asymmetric electrocatalysis was investigated. Two types of electrodes were prepared. The first electrode type was prepared according to the concept of organically doped metals. The chiral catalyst, a cinchona alkaloid, was entrapped in metal, which was then used as heterogeneous catalyst to press coin electrodes. Alternatively, the catalyst was coated onto a graphite electrode. These electrodes were tested for the electrocatalytic hydrogenation of ketones. The second electrode was prepared by coating an electrode with a chiral polymer, poly-L-valine. This electrode was tested for the asymmetric electrochemical oxidation of sulfides to sulfoxides. A chiral electrode could not be produced with these two concepts and further efforts would be required to confirm the methodologies. The reduction of molecular oxygen at the cathode can provide superoxide ions as reactive intermediates. The use of electrogenerated superoxide for the electrochemical oxychlorination of alkenes was tested in the second part of this work. The aim was to implement this type of reaction in continuous flow in order to investigate the biphasic gas-liquid interactions in a flow electrochemical reactor. However, this work focuses on the search for a homogeneous reaction solution for the batch electrochemical oxychlorination of styrene as a first step towards a flow procedure. Finally, the electrochemical generation of elemental bromine was utilised for a variety of transformations. Depending on the concentration of bromide ions and the choice of cosolvent, alkenes could be converted to the corresponding dibromides, bromohydrins or bromohydrin ethers. Alkenes containing internal nucleophiles would react to give bromo-cyclised products. The use of electrogenerated bromine provides a versatile synthetic procedure that can help to address some of the 12 principles of green chemistry

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Date of First Compliant Deposit:	7 February 2023
Last Modified:	07 Feb 2023 12:20
URI:	https://orca.cardiff.ac.uk/id/eprint/156543

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