FORMATION OF OCTACHLOROACENAPHTHYLENE IN THE PYROLYSIS OF DECACHLOROBIPHENYL

The pyrolytic degradation of decachlorobiphenyl (PCB 209) in the tempe rature range of 700 - 1000 degrees C and at a pyrolysis time of 10 sec onds generated one main chloroaromatic product. This compound has been identified by HPLC-UV, GC-MS, GC-FTIR and C-13-NMR as octachloroacena phthylene (OCAN). The mechanism of the nearly quantitative formation o f octachloroacenaphthylene (OCAN) occurs via a nonachlorobenzobarrylen e radical (ZIR) as an intermediate followed by a rearrangement and fur ther dechlorination to form OCAN, Calculations with the program THERM based on the Benson-group-theory indicated that this mechanism is not possible for lower or nonchlorinated biphenyls. (C) 1997 Elsevier Scie nce Ltd.