Characterization of Polyhalogenated 4-Methylphenol Dimers (Br/Cl-Predioxins) Formed during Aqueous Chlorination of 4-Methylphenol Solution in the Presence of Bromide Ion

Abstract

Aqueous 4-methylphenol solution with bromide ion was treated with hypochlorite at 20• C under various experimental conditions. Changes in the composition of the halogenated products in water were determined by gas chromatographic (GC) and GC-mass spectrometric (GC/MS) analyses of diethyl ether extracts. 4-Methylphenol was shown to produce a variety of halogenated compounds, including polybrominated/chlorinated phenoxyphenols (Br/Cl-predioxins), having one to four halogen atoms, as by-products in the chlorine-treated water. Production of these predioxins is dependent on the number of equivalent of chlorine atoms per mole of compound and on the reaction pH. These results suggest that the chlorine treatment of water contaminated with 4-methylphenol and bromide ion leads to the formation of Br/Cl-predioxins, which are precursor of the highly toxic halogenated dibenzo-pdioxins.

Aquatic Fate of Sunscreen Agents Octyl-4-methoxycinnamate and Octyl-4-dimethylaminobenzoate in Model Swimming Pools and the Mutagenic Assays of Their Chlorination Byproducts

“…16) In order to provide further insight into the possible role of organic compounds in the formation of chlorine-substituted compounds and that of chlorine-induced mutagens, we continued our study on the chemistry of aqueous chlorination of organic compounds. 17,18) The objectives of the present study are to quantify the reaction kinetics of octyl dimethyl-p-aminobenzoate (ODPABA) and octyl p-methoxycinnamate (OMC) with free available chlorine (HOCl) at various pH values, to identify the probable transformation products under conditions relevant to chlorine-based processes for swimming pool disinfection, and to evaluate mutagenic responses of both the reaction products and the parent compounds.…”

Transformation of Bisphenol AF during Aqueous Chlorination: Kinetics, Mechanisms, and Influence of pH

“…And under ET mechanism, BP was initially oxidized by chlorine and forms a phenoxyl radical, this radical would couple with each other to form the dimers, or break down by cleavage on the bridging carbon to form smaller molecules . Furthermore, the cleavage of BPs to smaller phenols may lead to the formation of chlorinated phenoxyphenols, which are precursors of notorious toxic chlorinated dibenzo- p -dioxins. − …”

Polietilen Tereftalat Liflerindeki Triklosanın Belirlenmesi ve Karakterizasyonu

“…Polychloro phenoxy phenols (polychlorinated phenoxy phenols, PCPPs) are a group of organic polyhalogenated compounds such as triclosan and predioxins. The chemical structures of the PCPP's isomers are presented in Figure 1 [1][2][3][4]. Triclosan (5-chloro-2-(2,4-dichlorophenoxy) phenol) is a chlorinated aromatic compound which has functional groups representative of both ethers and phenols.…”