Characterization of Polyhalogenated Phenoxyphenols (Br/Cl-Predioxins) Formed during Aqueous Chlorination of Phenol in the Presence of Bromide Ion

Abstract

Aqueous phenol solution with bromide ion was treated with sodium hypochlorite at 20°C under various experimental conditions. Changes in the composition and the concentration of the halogenated products in water were determined by gas chromatographic (GC) and GC-mass spectrometric (GC/MS) analyses of diethyl ether extracts. Phenol was shown to produce a variety of halogenated compounds, including polybrominated/chlorinated phenoxyphenols (PXPPs, Br/Cl-predioxins), having three to five halogen atoms, as byproducts in the chlorine-treated water. Production of these PXPPs is dependent on the number of equivalent chlorine atoms per mole of compound and on the reaction pH. These findings suggest that the chlorinetreatment of water contaminated with phenol and bromide ion leads to the formation of Br/Cl-predioxins, which are precursors of the highly toxic halogenated dibenzo-p-dioxins.