title: Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride.
abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5mM and 50mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl(-) led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins.
authors.affiliation: Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, 701B ERC building, 2901 Woodside Dr., Cincinnati, OH 45221, United States.
authors.forename: Linxi
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, 701B ERC building, 2901 Woodside Dr., Cincinnati, OH 45221, United States.
authors.forename: Pablo
authors.initials: P
authors.lastname: Campo
authors.affiliation: Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, 701B ERC building, 2901 Woodside Dr., Cincinnati, OH 45221, United States. Electronic address: margaret.kupferle@uc.edu.
authors.forename: Margaret J
authors.initials: MJ
authors.lastname: Kupferle
mesh_terms: D001895:Boron; D002712:Chlorides / Q000737:chemistry*; D002853:Chromatography, Liquid; D018130:Diamond; D004147:Dioxins / Q000737:chemistry; D004566:Electrodes; D054879:Halogenation; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D019800:Phenol / Q000737:chemistry*; D014260:Triclosan / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D002712:Chlorides; D004147:Dioxins; D014874:Water Pollutants, Chemical; D019800:Phenol; D014260:Triclosan; D018130:Diamond; D001895:Boron; C020887:dibenzo(1,4)dioxin
keywords: Anodic oxidation; Chlorinated oligomers; Liquid chromatography quadrupole time-of-flight mass spectrometry