Abstract
2, 4, 4'-Tricholoro-2'-hydroxydiphenyl ether (Irgasan DP300) (I) and its three chlorinated derivatives; 2', 3, 4, 4'-tetracholoro-2-hydroxydiphenyl ether (II), 2', 4, 4', 5-tetrachloro-2-hydroxydiphenyl ether (III) and 2', 3, 4, 4', 5-pentachloro-2-hydroxydiphenyl ether (IV), gave various polychlorinated dibenzo-p-dioxins (PCDDs) by exposure to sunlight and UV irradiation of their aqueous solutions. The four compounds gave further chlorinated dibenzo-p-dioxins other than PCDDs corresponding to the intramolecular dehydrochlorination upon exposure to sunlight. The amounts of PCDDs formed from I were varied by coexisting compounds in the aqueous solution upon exposure to sunlight. These results suggest that the four compounds are precursors of PCDDs upon not only thermal reaction such as incineration but also photolytic reaction under the environmental conditions.
