| The objectives of this research were to determine global pathways, through analyses of intermediate and final by-products, and evaluate the use of global kinetic models to describe the overall conversion from parent compounds to final stable products, for supercritical water oxidation of dimethyl methylphosphonate (DMMP) and thiodiglycol (TDG). These compounds were chosen as model compounds to simulate the nerve agent GB and mustard gas (agent HD), respectively.; Global destruction pathways were postulated for both parent compounds. Mass balances were performed for carbon, phosphorus and sulfur, where closures of 100 {dollar}pm{dollar} 10% were considered adequate to ensure that all major products were identified and analyzed. DMMP rapidly hydrolyzed to methanol and methylphosphonic acid (MPA) at subcritical temperatures. Oxidation of methanol and MPA produced carbon monoxide as an intermediate, and carbon dioxide and phosphoric acid as stable end-products. TDG hydrolysis/pyrolysis produced carbon monoxide, methane, ethanol, ethylene, and hydrogen sulfide. TDG oxidation resulted in carbon monoxide, methane, acetic acid, and sulfurous acid as intermediates, and carbon dioxide and sulfuric acid as stable end-products.; A detailed kinetic model, consisting of a set of simultaneous global rate equations, one for each major by-product, was developed to describe the behavior of DMMP and its transformation products in supercritical water. Arrhenius pre-exponential factors and activation energies, and reaction orders with respect to oxygen and each organic compound were determined. MPA was found to be the rate-limiting intermediate to the overall conversion of DMMP. Pilot-scale tests were conducted to validate the model. Model predicted yields for all by-products, agreed with the experimental data within 20%.; Corrosion, resulting in equipment failures and control problems, limited kinetic evaluations to identification of overall, rate-limiting intermediates for conversion of TDG to stable end-products. Carbon monoxide and methane were the primary rate-limiting intermediates for complete TDG conversion.; A new laboratory-scale, continuous-flow reactor was designed and constructed. This reactor system employed high-pressure, gaseous oxygen as the oxidant and provided for separation, collection, and analyses of both the liquid-phase and gas-phase effluents. |
