Thesis (Ph. D.)--Lehigh University, 1998. / Includes vita. Includes bibliographical references.

Thesis (Ph. D.)--Chemical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Dr. Christopher Jones; Committee Member: Dr. Dennis Hess; Committee Member: Dr. Hang Lu; Committee Member: Dr. Marcus Weck; Committee Member: Dr. Pradeep Agrawal. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Several heterogeneously catalysed reactions have been studied at pressures above and below the critical pressure of carbon dioxide in both carbon dioxide and nitrogen. The purpose of this study was to ascertain if carbon dioxide above its critical pressure and temperature would have a beneficial effect on the active life time of the catalysts When the Beckmann rearrangement of cyclohexanone oxime was studied it was discovered that using carbon dioxide above its critical pressure and temperature was beneficial to catalyst lifetime at both 250°C and 300°C, however the beneficial effect was also observed in nitrogen under the same conditions. It is proposed that the benefits at higher pressures are due to an increased residence time in the reactor or increased competition for active sites. When the process was performed at 380°C, a previously unreported impurity was observed in the collected samples. This was shown to be N-ethyl caprolactam, it is proposed that this is formed by a Ritter style reaction with 5-cyanopent-1-ene known to be formed during the reaction When the Fries rearrangement of phenyl acetate was studied it was discovered that increasing reactor pressure appeared to have little or no effect on the catalyst; it is thought this is because the reaction temperature of 150°C is below the boiling point of phenyl acetate, and that the reaction being observed occurs purely in the liquid phase. When the Diels-Alder addition of isoprene to methyl acrylate was studied, it was discovered that using carbon dioxide above its critical pressure had the effect of improving catalyst lifetime and conversion to desired product, with the greatest effect being at 50 bar. It was discovered that using nitrogen under the same conditions led to a greater improvement in conversion and catalyst lifetime. It is thought that the reactions in carbon dioxide are in a near critical state at 50 bar leading to the maximum effect at this pressure, and at higher pressures the reactions are bi- or multi-phasic, leading to the decrease in the effect. In the process of studying the above reactions an effective rig for the study of high pressure heterogeneously catalysed reactions was built.

This thesis investigates the preparation and characterisation of Co/Mo bimetallic carbides and their stability and catalytic activity as bulk catalysts for the Dry Methane Reforming (DMR) reaction and as supported catalysts on alumina. The DMR reaction was chosen due to its importance in producing syngas, as a precursor for liquid fuels, from CO₂ and CH₄, two greenhouse gases. Bulk and supported bimetallic carbides were prepared by reductive carburization of the oxides with various hydrocarbons. The resultant carbides were characterized by X-Ray diffraction. Reactivity studies were undertaken by investigating the variable temperature reactivity of the catalysts on the DMR reaction. Characterization studies indicate that the oxides were transformed to the carbides successfully and these carbides had significant catalytic activity and were stable under the conditions used in the investigations.

Thesis (Ph.D.); Submitted to Iowa State Univ., Ames, IA (US); 19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2397" Seong Huh. US Department of Energy 12/19/2004. Report is also available in paper and microfiche from NTIS.