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The addition of an aldehyde C−H bond across a ketone functionality, formally a hydroacylation, has emerged as an atom-economical approach to the synthesis of esters. While this is an efficient strategy for producing biologically-relevant materials, the field of transition metal-catalyzed ketone hydroacylation is currently limited to intramolecular systems. The development of a new rhodium catalyst will be presented, and its application to intermolecular ketone hydroacylation will be discussed. Ester products were synthesized from unfunctionalized, aliphatic aldehydes and chelating ketones in excellent yields under relatively mild reaction conditions. Efforts towards an asymmetric intermolecular ketone hydroacylation will be described, including the application of known chiral catalysts and the development of novel chiral phosphine ligands for asymmetric catalysis. Ester products were obtained in as high as 78% enantiomeric excess.

The electrochemical performance of a polymer electrolyte membrane fuel cell is known to be dominated by the cathode processes comprising the various reaction and transport steps in the overall oxygen electro-reduction to water occurring in the catalyst layer (CL). This thesis is concerned with one such transport process – oxygen transport in ionomer phase of the CL – and the synthesis/characterization of platinum catalyst on an alternative support – carbon nanotubes (CNT). Specifically, the objectives of the thesis are: (i) exploration of methods for determining the effective permeability of oxygen in the ionomer phase of the carbon-ionomer composite representing the PEMFC catalyst layer (ii) synthesis of Pt/CNT catalysts and characterization thereof. An electrochemical method for determination of oxygen permeability in Nafion and Nafion-carbon composite films was explored. Since the method is suitable for dense films, mathematical model for data analysis had to be modified to allow treatment of porous films. Applying the modified model to the porous Nafion film, the oxygen permeation in the Nafion phase was found to agree with the literature data for oxygen permeation in Nafion membranes. However, no relationship between the effective permeability and ionomer content was found. Two methods for synthesis of Pt/CNT catalysts were studied – the precipitation method and the colloidal/ethylene glycol method. Functionalization of CNTs was found to be critical to obtaining any significant amount of Pt deposition on CNT. The precipitation method did not yield reproducible results. Pt/CNT catalysts of desired properties were synthesized via the colloidal/EG method. It was found that a high pH of 8.5 to 10.5 resulted in smallest Pt particle size. The Pt particles size was determined to range 2-4 nm. The synthesized Pt/CNT catalysts were also tested in a fuel cell environment. Steady-state polarization curves in humidified H2/Air system were obtained that demonstrated performance comparable to commercial electrodes in that cell potential of greater than 0.6 V at current density of 800 mA/cm2 electrode area and a limiting current density of 1200 mA/cm2 electrode area were observed. / Thesis (Master, Chemical Engineering) -- Queen's University, 2009-01-13 14:46:53.853

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Rhodium, platinum, copper, palladium, and rhodium-ceria catalysts were investigated in the catalytic partial oxidation of methyl acetate, the simplest methyl ester, to better understand the conversion of biodiesel to hydrogen. Only rhodium and rhodium-ceria catalysts allowed for an autothermal reactor operation. Both catalysts were active in producing hydrogen, carbon monoxide, water, and carbon dioxide, although the rhodium-ceria catalyst showed the greater methyl acetate conversion and the greater hydrogen and carbon monoxide selectivities. A low C/O feed ratio favored the methyl acetate conversion, the hydrogen selectivity, and the carbon monoxide selectivity. Furthermore, a high gas hourly space velocity also improved the reactor performance. According to the experimental data, it appears that the oxidation of methyl acetate forms carbon monoxide and water as a primary step, instead of carbon dioxide and water as with the combustion reaction. In general, methyl acetate does not yield more synthesis gas than biodiesel. The methyl ester functional group limits the hydrogen yield and hence new catalysts should be developed and investigated in order to better target the decomposition of methyl esters to hydrogen.

<p>The objectives of this project was to ameroliate two waste materials, namely Acid Mine Drainage and Fly Ash and recover the solid residues for conversion into an adsorbent to treat brine. The solid residues were then converted into zeolite P through low temperature hydrothermal treatment. The adsorption capacity of the solid residues, zeolite P derived from the solid residues was compared to the commercial zeolite Y and fresh Arnot fly ash. The quality of the resulting water was assessed using different analytical methods before the reaction with adsorbents and after the reaction and a comparison was done based on the removal efficiency of elements Zeolite P from solid residues was successfully synthesized as confirmed by XRD, BET and FTIR. Brine treatment with fly ash, solid residues, zeolite P and commercial zeolite Y adsorbents was done concentration on the following major elements Na, K, Mg, Ca and Si. Zeolite P had higher or similar removal efficiency that the commercial zeolite Y for the following elements K, Ca and Mg. Fly ash is the only adsorbent that managed to reduce the concentration of Na in brine and also had a good removal efficiency of Mg. Si leached out of all the adsorbents which could be ascribed to Si being the major component of these adsorbents which could indicate some dissolution of these adsorbents under the conditions tested. Overall, zeolite P did not completely remove the major elements, especially for Na, but did result in a cleaner waste stream which would improve brine processing.</p>

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