Reaction of Chlorocarbons to HCI and Hydrocarbons in a Hydrogen-Rich Microwave-Induced Plasma Reactor

The separate reactions of chloroform (CHCl₃), trichloroethylene (C₂HCl₃), and chlorobenzene (C₆H₅Cl) with water vapor or molecular hydrogen have been studied in a low-pressure [ca. 5 Torr (0.67 kPa)] microwave plasma tubular flow reactor. The experimental apparatus included feed introduction systems, a microwave plasma reactor, and full product analyses by flame ionization and thermal conductivity gas chromatography, mass spectrometry, and specific ion or pH detection for hydrogen chloride (HCl). Conversions of the parent chlorocarbon in the range of 50 to almost 100% were achieved. The high temperatures required for adequate conversion in a conventional thermal detoxification system were not necessary in this study. Product analyses indicate conversion to HCl, light hydrocarbons, some nonparent chlorocarbons, and soot. For the H₂O case, carbon monoxide and trace carbon dioxide were produced in place of some light hydrocarbons and soot. At least 85 mol % of the chlorine (Cl) from the converted parent forms thermodynamically stable HCl at parent conversions of 80% or more. The remaining chlorine was present as nonparent chlorocarbons. Reaction mechanisms are proposed for the conversion of the parent chlorocarbon and the formation of observed products.