Aqueous Phase Oxidation of Organics (Wet-Air, Vapor-Liquid Equilibrium, Synergism, Free Radical, Xylene, Phenol).

Fundamental disappearance kinetics parameters have been obtained for four compounds individually subjected to aqueous phase oxidation. These four compounds are m-xylene, phenol, tetrachloroethylene, and malathion. Concentration histories were obtained using a one liter sampled-batch reactor. Reaction conditions ranged from 114-290 (DEGREES)C and 1000-2500 psi air. A kinetics model incorporating vapor-liquid equilibrium effects was developed and used to determine reaction rate constants. The reactions were found to be first order in organic and 1/2 order in oxygen. Induction periods were observed for m-xylene and phenol. The durations of these periods were found to be inversely proportional to oxygen concentration. Activation energies were determined for all compounds except malathion which reacted at rates faster than could be measured. Two reaction rate enhancement techniques were investigated, namely initiation and synergism. The former was explored by adding hydrogen peroxide to m-xylene reactions. It was discovered that small amounts of initiator eliminated the induction period without affecting the subsequent reaction rate. Synergism experiments entailed reacting m-xylene and phenol simultaneously. When starting with equimolar quantities of each, the m-xylene reaction rate was increased by about 1.5 orders of magnitude while phenol rates were only slightly decreased. A final set of experiments determined that additions of soil to m-xylene reactions dramatically reduced reaction rates. Tetrachloroethylene, however, was unaffected by such additions. A free radical mechanism involving hydroperoxides and degenerate chain branching was shown to accurately describe the individual m-xylene and phenol reaction results