Catalytic Dechlorination of Polychlorinated Biphenyls on Activated Carbon

A significant dechlorination (87%) of most persistent 2,4,5 trichlorobiphenyl was achieved at 110 °C in water/ isopropanol solvent by applying reducing media in presence of activated carbon. It was observed that carbon particles played a catalytic role in enhancing the dechlorination through substitution reactions and by suppressing further chlorination in reaction mixture. Furthermore without using activated carbon dechlorination was decreased and the substituted products were not observed. Results suggested that dechlorination at ortho position of biphenyl was clearly preceded through substitution by hydroxyl and thiol ions. The reaction mechanism was predicted.