| The work presented in this dissertation focuses on the application of polyoxometalate (POM) catalysts, especially {dollar}rm Hsb5PVsb2MOsb{lcub}10{rcub}Osb{lcub}40{rcub}{dollar} (1), to the oxidative destruction of thioether mustard (HD) analogs. This research began with fundamental kinetic and mechanistic studies and evolved to supporting {dollar}rm Hsb5PVsb2Mosb{lcub}10{rcub}Osb{lcub}40{rcub}{dollar} on carbon cloths that may eventually be used as a component of catalytically self decontaminating clothing.; The kinetics and mechanism for the oxidation of tetrahydrothiophene, THT, by {dollar}rm Hsb5PVsb2Mosb{lcub}10{rcub}Osb{lcub}40{rcub},{dollar} outlined in Chapter 2, reveals a novel mechanism and water effect. The rate law for this initial non-catalytic step was found to be first order in THT and 1 but negative first order in water. Interestingly, in this system the substrate is directly oxidized by the catalyst (1) which is subsequently reoxidized by the terminal oxidant, t-butylhydroperoxide, TBHP.; Chapters 3 and 4 address the immobilization of {dollar}rm Hsb5PVsb2Mosb{lcub}10{rcub}Osb{lcub}40{rcub}{dollar} on carbon powders and cloths and the characterization and catalytic activity of these novel heterogeneous systems. Again, the kinetics and mechanism were studied. The rate law for the catalytic heterogeneous reaction was first order in substrate, oxidant, and catalyst. All data were consistent with a mechanism similar to the homogeneous reaction involving initial direct oxidation of the substrate, THT, by polyoxometalate. The 1/carbon powder catalysts were found to combine the selectivity of homogeneous POMs with the stability and recoverability of heterogeneous catalytic systems.; The {dollar}rm Hsb5PVsb2Mosb{lcub}10{rcub}Osb{lcub}40{rcub}{dollar}/carbon cloth systems proved as effective and amenable to detailed experimental evaluation as the {dollar}rm Hsb5PVsb2Mosb{lcub}10{rcub}Osb{lcub}40{rcub}{dollar}/carbon powder systems. The ability of the cloths to retain {dollar}rm Hsb5PVsb2Mosb{lcub}10{rcub}Osb{lcub}40{rcub}{dollar} was evaluated in water, acetonitrile, and toluene. This enabled conclusions to be drawn about the stability of the various 1/carbon materials in the rain. As with the powders, the cloths could easily be reactivated after use by heating to 80{dollar}spcirc{dollar}C in a vacuum oven. The effect of carbon hydrophobicity and thioether steric and electronic factors on reactivity were examined.; The final chapter of this dissertation details our efforts to find a catalytic thioether oxidation system that would be operable using air/oxygen as the terminal oxidant. In doing so, we report the first application of combinatorial chemistry to polyoxometalate synthesis and inorganic catalysis.; Abstracts with technical and experimental details of the research are found at the beginning of chapters 2-5. |
