Functional metallomacrocycles and their polymers, Part 37. Oxidative decomposition of 2,4,6-trichlorophenol by polymer-bound phthalocyanines

Oxidative decomposition of 2,4,6-trichlorophenol (TCP) catalyzed by iron, manganese, and cobalt octacarboxyphthalocyanines and their polymer-bound derivatives was studied in aqueous solution. Iron octacarboxyphthalocyanine scarcely had catalytic activity in oxidative decomposition of TCP by H2O2, while extremely high catalytic activity was observed in the presence of water-soluble polymers having pyridinium side chains. When iron octacarboxyphthalocyanine complex was covalently bound to the water-soluble cationic polymer, it revealed much higher catalytic activity. 2,6-Dichloro-p-benzoquinone was formed in the initial period of the reaction and was decomposed to further low molecular weight compound. Formic acid, oxalic acid, chloropropenic acid, and two coupling products were found in the resulting solution by CC-MS analysis. Catalytic activity of polymer-bound iron phthalocyanine was strongly influenced by pH and the maximum activity was observed at pH 7. The pH-dependence of the catalytic activity was explained by the dissociation of TCP. Enhancement in catalytic activity by polymer chain was also observed in manganese and cobalt phthalocyanine complexes. Highly efficient dechlorination of TCP was concomitantly achieved by the polymer-bound iron and manganese phthalocyanine complexes, while polymer-bound cobalt phthalocyanine complex hardly cause the dechlorination. (C) 2000 Elsevier Science B.V. All rights reserved.