Title: Oxidation of 4-bromo-4'-chlorobiphenyl, model species for forming mixed halogenated aromatic compounds

Authors: Song Hou; Bogdan Z. Dlugogorski; John C. Mackie; Eric M. Kennedy; Stina Jansson; Mohammednoor Altarawneh

Addresses: School of Engineering, The University of Newcastle, Australia Callaghan, NSW 2308, Australia; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China ' School of Engineering and Information Technology, Murdoch University, Murdoch, WA 6150, Australia ' School of Engineering, The University of Newcastle, Australia Callaghan, NSW 2308, Australia ' School of Engineering, The University of Newcastle, Australia Callaghan, NSW 2308, Australia ' Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden ' School of Engineering and Information Technology, Murdoch University, Murdoch, WA 6150, Australia

Abstract: This contribution reports results from the gas-phase oxidation of 4-bromo-4'-chlorobiphenyl (4,4'-BCB) in order to fathom the formation of toxic species produced during the combustion of mixed halogenated aromatics. In their own right, mixed polybrominated/polychlorinated biphenyls (PXBs) represent a new class of environmental contaminants, recently detected in food and human tissues. Gas chromatography-quadrupole mass spectrometry (GC-QMS), gas chromatography-quadrupole time of flight mass spectrometry (GC-QTOFMS), Fourier transform infrared spectroscopy (FTIR) and ion chromatography (IC) served to analyse the volatile and semi-volatile organic compounds (V/SVOCs), including mixed halogenated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs), and gaseous products including HBr/HCl. The selection of non-ortho substituted PXB as a model species yields a large number of halogenated compounds, including monochloro- and monobromobenzene and higher halogenated benzenes and naphthalenes and derivatives of halogenated benzenes (such as 1-chloro-4-ethynylbenzene). We also detect small amounts of chlorinated and mixed halogenated dibenzofurans. The present study provides insights into the formation of several classes of halogenated and mixed-halogenated pollutants in combustion processes involving both bromine and chlorine sources, such as those of brominated flame retardants and PVC plastics.

Keywords: brominated and chlorinated biphenyls; halogenated VOC and SVOC; PXBs; 4-bromo-4'-chlorobiphenyl; halogenated aromatic compounds; formation mechanisms of trace pollutants.

DOI: 10.1504/IJEP.2017.087760

International Journal of Environment and Pollution, 2017 Vol.61 No.3/4, pp.243 - 260

Available online: 27 Oct 2017 *

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