Formation of polybrominated and polychlorinated ethylphenoxyethylphenols (PXEPEPs) during aqueous chlorination of 4-ethylphenol solutions in the presence of bromide ions

Abstract

This investigation was undertaken to determine the effect of the bromide concentration on the formation of polyhalogenated ethylphenoxyethylphenols (PXEPEPs), including predioxins, during the chlorination of 4-ethylphenol in solution. An aqueous solution of 4-ethylphenol was treated with hypochlorite in the presence of various concentrations of bromide ions. The changes in the compositions of the halogenated products in hexane extracts of the chlorinated solution were analyzed by gas chromatograph (GC) and a flame ionization detector (FID) and mass spectrometry (MS). 4-ethylphenol was shown to from several halogenated compounds, including PXEPEPs, as by-products of chlorination. The number of substituted chlorine or bromine atoms ranged from 0 to 4. The formation of bromine-substituted PXEPEPs was observed in the presence of 0.1 equivalents of bromide ions per mole of 4-ethylphenol. The number of substituted bromine atoms increased with the amount of co-existing bromide ions. In the presence of more than one equivalent of bromide ions per mole of 4-ethylphenol, the number of bromine atoms substituted in the PXEPEPs increased, whereas the number of chlorine atoms substituted in the PXEPEPs decreased. GC-MS total ion chromatograms confirmed the formation of polybrominated and polychlorinated predioxins during the aqueous chlorination of 4-ethylphenol in the presence of bromide ions. However, at ten equivalents of bromide ions per mole of 4-ethylphenol, no predioxins were observed in the hexane extract obtained from the aqueous 4-ethylphenol solution after being treated with chlorine. The formation of PXEPEPs during the chlorination of 4-ethylphenol in the presence of bromide ions was also influenced by the reaction pH.

Sorption of Aromatic Compounds with Copolymer Sorbent Materials Containing β-Cyclodextrin

“…The buildup and transport of chlorophenol-based pollutants (e.g., biocides, petrochemicals, and pharmaceuticals) represent an important environmental issue which may adversely impact aquatic ecosystems, biodiversity, and human health [3,4,5,6,7,8]. One of the eight millennium goals of the United Nations Environment Program (UNEP) is the provision of clean drinking water and its mandate is to reduce the proportion of people without sustainable access to safe drinking water by half in 2015 [9].…”

“…Phenolic compounds are ubiquitous in nature and are widely used as raw materials in the chemical industry [ 1 ] and other applications including petrochemical processing, kraft pulp and paper production, and olive oil products [ 1 , 2 ]. The buildup and transport of chlorophenol-based pollutants (e.g., biocides, petrochemicals, and pharmaceuticals) represent an important environmental issue which may adversely impact aquatic ecosystems, biodiversity, and human health [ 3 , 4 , 5 , 6 , 7 , 8 ]. One of the eight millennium goals of the United Nations Environment Program (UNEP) is the provision of clean drinking water and its mandate is to reduce the proportion of people without sustainable access to safe drinking water by half in 2015 [ 9 ].…”

“…Therefore, there is an urgent need to develop novel materials and innovative methods to address the removal of phenols from contaminated aquatic environments. Chlorophenol and its conjugates have been used as wood preservatives and biocides despite their acute toxicity and widespread occurrence [ 3 , 4 , 5 , 6 , 7 , 8 ]. For example; 2,4-dichlorophenol (2,4-DCP) is a toxic organic compound that has been widely used as an agrochemical and as a preservative for wood, leather and glue.…”

Phenolic Pollutant Uptake Properties of Molecular Templated Polymers Containing β-Cyclodextrin

“…The buildup of such species in ground and surface water supplies relates to the uncontrolled release of industrial effluents from various sources. The widespread use of phenolic additives in textile dyes, explosives, agrochemicals, and pharmaceuticals represent an emerging concern to human and ecosystem health due to buildup in surface and groundwater supplies. − The utility of model systems, such as PNP and trinitrophenol (TNP), relate to their variable solubility profile , and mobility in aquatic environments, where the occurrence of such species has revealed the need to develop advanced materials for remediation of aquatic environments. Recent studies on sorbent materials indicate that favorable host–guest molecular interactions − between cyclodextrins (CDs) and phenols occur, especially in the case of CD polymer-based materials.…”

Chemical fate and mutagenic formation potentials of phenothiazine and related compounds during water chlorination

“…In order to provide further insight into the possible role of organic compounds in the formation of chlorine-substituted compounds and chlorine-induced mutagens, this laboratory has continued the study of the aqueous chlorination chemistry of organic compounds (Nakamura et al, 2008;Nakajima et al, 2009;Kawakami et al, 2009). The present report describes a detailed study of the products distribution for four hetero-tricyclic aromatic hydrocarbons (H-TCAHs), which were selected because of their widespread use in pharmaceutical and textile manufacturing industries, and as a suppressor in the polymerization of vinyl acetate, acrolein and acrylic acid.…”