| The pyrolysis and oxidation of dichloromethane is studied in a tubular reactor at 1 atmosphere pressure, residence time between 0.3 to 2.0 seconds and in the temperature range 680-840{dollar}spcirc{dollar}C. Four reactant concentration ratios are:(UNFORMATTED TABLE OR EQUATION FOLLOWS){dollar}{dollar}vbox{lcub}halign{lcub}#hfil&&enspace#hfilcr& I. CH{dollar}sb2{dollar}Cl{dollar}sb2{dollar}{lcub}:{rcub}Ar&= 1{lcub}:{rcub}99& II. CH{dollar}sb2{dollar}Cl{dollar}sb2{dollar}{lcub}:{rcub}CH{dollar}sb4{dollar}{lcub}:{rcub}Ar&= 1{lcub}:{rcub}1{lcub}:{rcub}98cr&III. CH{dollar}sb2{dollar}Cl{dollar}sb2{dollar}{lcub}:{rcub}O{dollar}sb2{dollar}{lcub}:{rcub}Ar&= 1{lcub}:{rcub}4{lcub}:{rcub}95&IV. CH{dollar}sb2{dollar}Cl{dollar}sb2{dollar}{lcub}:{rcub}CH{dollar}sb4{dollar}{lcub}:{rcub}O{dollar}sb2{dollar}{lcub}:{rcub}Ar&= 1{lcub}:{rcub}1{lcub}:{rcub}4{lcub}:{rcub}94cr{rcub}{rcub}{dollar}{dollar}(TABLE/EQUATION ENDS); The degradation of dichloromethane, intermediate product formation and decomposition, and final products are studied in both pyrolytic and oxidative reaction environments. Chlorinated intermediate products: {dollar}rm CHsb3Cl, Csb2HCl, Csb2Hsb3Cl, CHsb2CClsb2, CHClCHCl{dollar}, and {dollar}rm Csb2HClsb3{dollar} are shown to be important in all systems but more difficult to destroy in the pyrolysis than in the oxidation. The conversion of these chloro-methyl radicals to corresponding chloro-formaldehydes, CO and CO{dollar}sb2{dollar} is observed to be slow by this reaction sequence. The demonstration of this bottleneck is another important result of this thesis. Results show that conversion primarily occurs through combination of 2 chloro-methyl radicals to chloro-ethanes, then ethylenes, then chloro-vinyl radicals. The major chloro-methyl radical conversion path under combustion condition is the chloro-vinyl radical + O{dollar}sb2{dollar}. Thermodynamic parameters: {dollar}Deltarm Hsb{lcub}298{rcub}, Ssb{lcub}298{rcub}{dollar} and C{dollar}sb{lcub}rm p{rcub}{dollar}(T) for all species in the reaction mechanism are evaluated and illustrated.; A reaction mechanism consisting of 635 elementary reactions and 215 species, to C{dollar}sb6{dollar} compounds, has been developed to simulate the thermal decomposition of dichloromethane and for use in predicting the formation of aromatics and intermediate molecular weight growth species in C{dollar}sb1{dollar} and C{dollar}sb2{dollar} chlorocarbon combustion. All reactions in the mechanism are elementary or derived from analysis of reaction systems encompassing elementary reaction steps. All reactions are thermochemically consistent and follow principles of Thermochemical Kinetics. Model data show good agreement for reagent decay and major product distribution in both pyrolytic and oxidative environments.; Unimolecular dissociation of CH{dollar}sb2{dollar}Cl{dollar}sb2{dollar} and of chlorinated ethylenes is analyzed by unimolecular quantum RRK. Combination and addition reactions such as: {dollar}rm CHsb2Cl + Osb2, CHClsb2 + Osb2, CHsb3 + CHsb2Cl, CHsb3 + CHClsb2, CHsb2Cl + CHsb2Cl, CHsb2Cl + CHClsb2, CHClsb2 + CHClsb2, Csb2Hsb3 + Osb2, CHsb2CCl + Osb2, CHClCH + Osb2, CHClCCl + Osb2, CClsb2CH + Osb2{dollar}, and {dollar}rm Csb2Clsb3 + Osb2{dollar} are treated with bimolecular quantum RRK analysis for k(E), combined with modified strong collision approach and/or Master equation analysis for fall-off effects.; Hydrocarbon and chlorocarbon radical addition to unsaturated species is responsible for molecular weight growth and ultimate formation of precursors to polychlorinated dibenzo dioxins and furans.; Reactions of {dollar}rm HSO + O, SO + OH, H + SOsb2, OH + SOsb2, H + SOsb3, OH + HSO{dollar}, and H + HOSO are analyzed as functions of pressure and temperature. |
