PALLADIUM-CATALYZED DECHLORINATION OF POLYCHLOROBIPHENYLS - A STUDY OF THE KINETIC MECHANISM

The dechlorination of polychlorobiphenyls (PCBs) used in the electrica l industry is studied in different media. Dechlorination of PCBs in ai r is obtained with high yields during a short period: for example, 98. 4% in 4 h in the case of transformer pyralen containing 60% of chlorin e (equivalent of Aroclor 1260). The reaction process involves an acidi c palladium-zinc catalytic system. The dechlorination of PCBs is compl ex but the kinetic mechanism discussed in this work gives a good under standing of the experimental results. The method is not applicable to PCBs in mineral oils containing naphthenic structures as aromatic mole cules inhibit the catalyst.