THERMAL-REACTIONS OF CH2CL2 IN H-2/O-2 MIXTURES - IMPLICATIONS FOR CHLORINE INHIBITION OF CO CONVERSION TO CO-2

The thermal decomposition of dichloromethane in hydrogen/oxygen mixtures and argon bath gas was carried out at 1 atm pressure in tubular flow reactors of varied surface-to-volume ratios. The degradation of dichloromethane plus intermediate and final product formation was analyzed from 873 to 1093 K, with average residence times of 0.1-2.0 s. A detailed kinetic reaction mechanism based upon fundamental thermochemical principles and Transition State Theory was developed and used to model our experimental results. Sensitivity analysis was used to determine important reactions effective in inhibiting CO conversion to CO2. The results indicate that the reaction: OH + HCl --> H2O + Cl is a major cause of OH loss and this decrease in OH significantly reduces CO conversion by reaction with OH. Lower temperatures result from reduced CO reaction with OH, which increases the importance of HO2. Here. the reaction of HO2 + Cl to the HCl + O2 (termination) channel further inhibits combustion. A significant fraction of the CH2Cl2 conversion occurs through C2 chlorocarbon formation, which results from methyl and chloromethyl combination reactions.