FORMATION OF PCDFS DURING CHLORINATION AND OXIDATION OF CHLOROBENZENEIN CHLORINE OXYGEN MIXTURES AROUND 340-DEGREES-C

Homogenous gas-phase chlorination of chlorobenzene in the presence of oxygen at 330-350 degrees C gives substantial amounts of PCDFs, up to 6% on the major product, the dichlorobenzenes. Chlorine atoms abstract H from chlorobenzene, the resulting chlorophenyl radicals reacting ra pidly with Cl-2 or with O-2. The latter reaction leads to chlorophenox yl radicals. Part of these appear to be further chlorinated before con densation occurs to mainly D2CDF, T3CDF and T4CDF. The simultaneous pr oduction of CO and (extra) HCl shows that (chlorine initiated) slow co mbustion also takes place, presumably by reaction of chlorinated pheny lperoxyl- and/or phenoxyl radicals with oxygen.