Project I: [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 as a Homogeneous Hydrogenation Catalyst for Biomass Derived Substrates.
The complex [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 has been shown to be an active ionic hydrogenation catalyst for selected carbonyls, diols and glycerol by the Schlaf group. It was postulated to also be active for other biomass derived substrates such as levulinic acid (LA), furfural and 5-hydroxymethyl furfural (HMF). Synthesis of the complex was optimized and full characterization carried out by 1H/13C –NMR. The complex was tested against LA in aqueous sulfolane medium and the furfural/HMF model system 2,5-hexanedione in water. Activity of the complex was compared to the analogous metal-ligand bifunctional (MLB) system described in
Project II. The complex exhibited good thermal stability up to 200 oC in 90/10 wt%
sulfolane/water mixtures and was capable of hydrogenation of LA to γ-valerolactone in 95% yield. Addition of protic acids to the reaction mixture and increasing proportions of water decreased the activity of the complex towards the hydrogenation of LA.
Project II: [Ru(OH2)3(di(picolyl)amine)](OTf)2 as an acid-, water- stable, metal-ligand bifunctional deoxygenation catalyst.
The complex [Ru(OH2)3(di(picolyl)amine)](OTf)2 was postulated to be an active MLB ionic hydrogenation catalyst under acidic aqueous conditions. Using the substantially labile [Ru(DMF)6](OTF)3 ruthenium complex as the precursor, the desired complex was prepared insitu by coordination of the DPA ligand and concomitant reduction of Ru3+ to Ru2+. The complex was characterized by 1H/13C-NMR and tested for the hydrogenation of LA, 2,5-hexanedione, furfural and HMF under acidic aqueous conditions. The complex exhibited thermal stability up to 150 oC and was active for the hydrogenation of carbonyls, as demonstrated by the conversion of 2,5-hexanedione to 2,5-hexanediol in 94% yield in water. Addition of H3PO4 as an acid cocatalyst resulted in nearly complete conversion to dimethyltetrahydrofuran (DMTHF) but further deoxygenation could not be achieved. Direct comparision of [Ru(OH2)3(di(picolyl)amine)](OTf)2 and [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 under identical conditions against LA and 2,5-hexanedione demonstrated that the[Ru(OH2)3(di(picolyl)amine)](OTf)2 catalyst is more active than the [Ru(OH2)3(4'-phenyl-2,2':6',2''-terpyridine)](OTf)2 complex in all cases, suggesting that the di(picolyl)amine complex operates through a MLB ionic hydrogenation mechanism. / NSERC
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OGU.10214/7438 |
| Date | 30 August 2013 |
| Creators | Oswin, Chris |
| Contributors | Schlaf, Marcel |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | Attribution-NoDerivs 2.5 Canada, http://creativecommons.org/licenses/by-nd/2.5/ca/ |
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