published_or_final_version / Chemistry / Master / Master of Science

published_or_final_version / Chemistry / Master / Master of Science

published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy

No description available.

Summary Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to measure the concentrations of cobalt, tantalum, titanium, vanadium and chromium in solutions of tungsten carbide. The main advantage of the method described here lies in the speed, convenience and effectiveness of the dissolution procedure. Aliquots of powdered tungsten carbide were dissolved in a solution of 5% aqua regia in 30% hydrogen peroxide. Complete dissolution was usually achieved within 10 min. The accuracy of the method was assessed by the analysis of certified reference materials, secondary reference materials and matrix spiking. The method was successfully applied to commercial type samples with differing compositions. Slightly more emphasis was placed on the measurement of vanadium, since no information on the measurement of this element in solutions of tungsten carbide, by ICP-OES, has been published. Investigation of the interference effects of the elements in the sample matrix on each other was essential for accurate results comparable to other published analytical methods.

The purpose of this investigation is two-fold. Some new complex compounds, where one of the bidentate molecules is an optically active amino acid, were prepared, and attempts to separate those complex isomers by different methods were made. The replacement of the amino acids by optically inactive ligands was studied.

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Masters of Science in Engineering. / The partial oxidation of methane by air to synthesis gas over supported cobalt catalysts was studied. The investigation included analysis of the products of this reaction at various temperatures, and of the structure of the catalysts using powder X-ray diffraction techniques. (Abbreviation abstract) / Andrew Chakane 2018

A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Masters of Science in Engineering. / The partial oxidation of methane by air to synthesis gas over supported cobalt catalysts was studied. The investigation included analysis of the products of this reaction at various temperatures, and of the structure of the catalysts using powder X-ray diffraction techniques. The most effective catalyst for this reaction was found to be metallic cobalt supported on rhombohedral alumina (prepared as lO%Co/C/'r-A103)' In the presence of this catalyst 96% of tile feed was completely converted to synthesis gas (CO: 2H2) at lOOO°C. This catalyst showed no evidence of coking or loss of activity at lOfO°C over a period of 180 hours. The reaction mechanism is thought to occur in two stages over two distinct zones of the catalyst, Complete reaction of O2 with CH4 to form CO2 and H20 is followed, in the second stage, by reforming and the water gas shift reaction to produce synthesis gas. / Andrew Chakane 2018