Development and characterization of supported-metal and olefin-polymerization catalysts

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Catalysts are widely used in the production of materials needed for making consumer goods (e.g. plastics, artificial fibres, gasoline, fertilizer, etc.). Catalysts improve the utilization of raw materials by providing selective and low-energy routes for conversion to desired products. Hence, catalysts are a key player in green chemistry and improved sustainability of chemical and polymer production. Catalysts are also frequently used in the elimination of pollutants; the most well know application of this use is the automobile catalytic converter. The currently proposed research addresses both of the above aspects of catalysts. The first area of the proposed research deals with studies on olefin polymerization catalysts. The objective of these studies is to gain insight into the factors which govern the performance of polymer-supported metallocene catalysts for gas-phase ethylene polymerization. We have developed various polymer-supported catalysts which are suitable for gas-phase polymerization, but the factors which determine the shape and structure (morphology) of the product particles are not well understood. The proposed research will address this lack of understanding. The morphology of the polymer particles is very important for the use of these catalysts in fluidized bed reactors; being able to control the morphology will allow the elimination of pelletization of the product (a very energy intensive step), as well as open the door for the production of specialized micron-sized, macro-porous polyethylene particles. The second area of the proposed research also deals with supported catalysts, but in this case the application of these catalysts is in the elimination of hydrocarbon pollutants by complete oxidation using diffusive catalytic reactors. Diffusive catalytic reactors, rather than the conventional flow reactors, are widely used in the petroleum industry for space heating. These devices are poorly understood, but they offer great potential for elimination of hydrocarbons at low concentration by catalytic combustion. However, improved catalysts with better resistance to sulfur and lower tendency for coking are required. The proposed research will explore new catalyst formulations for diffusive catalytic reactors.