10.1021/acs.est.5b03637.s001

Monohydroxylated Polybrominated Diphenyl Ethers (OH-PBDEs) and Dihydroxylated Polybrominated Biphenyls (Di-OH-PBBs): Novel Photoproducts of 2,6-Dibromophenol

Abstract

Hydroxylated polybromodiphenyl ethers (OH-PBDEs) are emerging aquatic pollutants, but their origins in the environment are not fully understood. There is evidence that OH-PBDEs are formed from bromophenols, but the underlying transformation processes remain unknown. Here, we investigate if the photoformation of OH-PBDEs from 2,6-dibromophenol in aqueous solution involves 2,6-bromophenoxyl radicals. After the UV irradiation of an aqueous 2,6-dibromophenol solution, HPLC–LTQ-Orbitrap MS and GC–MS analysis revealed the formation of a OH-PBDE and a dihydroxylated polybrominated biphenyl (di-OH-PBB). Both dimeric photoproducts were tentatively identified as 4′-OH-BDE73 and 4,4′-di-OH-PBB80. In addition, three debromination products (4-OH-BDE34, 4′-OH-BDE27, and 4,4′-di-OH-PBBs) were observed. Electron paramagnetic resonance spectroscopy revealed the presence of a 2,6-dibromophenoxyl radical with a six-line spectrum (a<sup>H</sup> (2 <i>meta</i>) = 3.45 G, a<sup>H</sup> (1 <i>para</i>) = 1.04 G, <i>g</i> = 2.0046) during irradiation of a 2,6-dibromophenol solution in water. The 2,6-dibromophenoxyl radical had a relatively long half-life (122 ± 5 μs) according to laser flash photolysis experiments. The <i>para–para</i> C–C and O–<i>para</i>-C couplings of these 2,6-dibromophenoxyl radicals are consistent with the observed formation of both dimeric OH-PBDE and di-OH-PBB photoproducts. These findings show that bromophenoxyl radical-mediated phototransformation of bromophenols is a source of OH-PBDEs and di-OH-PBBs in aqueous environments that requires further attention

Similar works

Full text

thumbnail-image
oai:figshare.com:article/2099407Last time updated on 2/12/2018

This paper was published in FigShare.

Having an issue?

Is data on this page outdated, violates copyrights or anything else? Report the problem now and we will take corresponding actions after reviewing your request.