AbstractThis thesis concerns the synthesis of ethylene glycol using homogeneous catalysts. Three different routes were studied each based around a different starting material, which could potentially be prepared from renewable sources.
Chapter 2 details attempts to synthesise ethylene glycol by the reductive hydroformylation of formaldehyde using both cobalt and rhodium catalysts. Despite extensive condition screening and modification to the catalyst systems, these efforts were largely unsuccessful.
Chapter 3 consists of the synthesis of a range of ruthenium complexes with tridentate phosphorus-based ligands and their application as catalysts for the hydrogenation of C2 oxalates to ethylene glycol. Focus was given to a family of air stable dimer complexes featuring tripodal, tridentate phosphine ligands which showed good performance for these hydrogenation reactions. Preliminary mechanistic studies and kinetic investigation were also conducted as well as brief, but successful tests performing these ester hydrogenations in flow.
Chapter 4 is based on finding a synthetic pathway from glycerol to ethylene glycol via a combination of stoichiometric organic reactions and homogeneous catalysis. The results were mixed with no clear route all the way from glycerol to ethylene glycol achieved.
Chapter 5 discusses several other reactions of interest using the ruthenium complexes first introduced in Chapter 3 as catalysts. Some success was achieved with the heterocoupling of methanol and ethanol to isobutanol while the hydrogenation of C3 diesters and amides proved more challenging. The transfer hydrogenation of an aldehyde using ammonium formate was tested which showed unexpected reactivity producing secondary amines as well as the desired alcohol.
|Date of Award||24 Mar 2020|
|Supervisor||Duncan F Wass (Supervisor)|