FORMATION OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS FROMTHE PYROLYSIS OF HEXACHLOROCYCLOHEXANE IN THE PRESENCE OF IRON(III) OXIDE

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzof urans (PCDFs) are formed by the pyrolysis of non-gamma isomers of hexa chlorocyclohexane (HCH) in the presence of iron(III) oxide The yield o f PCDD/Fs depends on the concentration of iron(III) oxide, temperature and reaction time The maximum yield is 4.5 mu g/mg HCH. A possible pa thway for the formation of PCDD/Fs is Suggested. Iron(III) oxide is sh own not only to be able to increase amounts of chlorophenols but also to catalyze the condensation reaction of chlorophenols into PCDD/Fs.