Vapor Pressures of the Polybrominated Diphenyl Ethers (original) (raw)
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Synthesis and Characterization of 32 Polybrominated Diphenyl Ethers
Environmental Science & Technology, 1999
Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame retardants in, for example, textiles, computers, television sets, and other electrical appliances. PBDEs are ubiquitous environmental contaminants, present also in humans. The environmental levels of the PBDEs are, however, still in general lower than those of polychlorinated biphenyls (PCBs). However, while the levels of PCBs generally are decreasing, those of the PBDEs are increasing in, for example, human milk. In the present study 32 individual PBDE congeners were synthesized and characterized. Physicochemical parameters including melting points and UV, 1 H NMR, and mass spectra are reported. Twenty-nine monobrominated to heptabrominated diphenyl ethers were synthesized by the coupling between four diphenyliodonium salts and nine phenolates. One tetrabromodiphenyl ether and two hexabromodiphenyl ethers were synthesized by bromination of two different PBDEs. Twenty-one of the PBDEs and two of the iodonium salts, 2,2′,4,4′-tetrabromodiphenyliodonium chloride and 3,3′,4,4′tetrabromodiphenyliodonium chloride, are to the authors' knowledge described for the first time. These synthesized reference compounds will aid in the identification and quantification of PBDEs present in environmental samples and will allow further assessment of PBDE toxicity.
Chemosphere, 2010
The octanol-air partition coefficient (K OA ) of 19 hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and 10 methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were measured as a function of temperature using a gas chromatographic retention time technique. At room temperature (298.15 K), log K OA ranged from 8.30 for monobrominated OH/MeO-PBDEs to 13.29 for hexabrominated OH/MeO-PBDEs. The internal energies of phase change from octanol to air (D OA U) for 29 OH/MeO-PBDE congeners ranged from 72 to 126 kJ mol À1 . Using partial least-squares (PLS) analysis, a statistically quantitative structure-property relationship (QSPR) model for log K OA of OH/MeO-PBDE congeners was developed based on the 16 fundamental quantum chemical descriptors computed by PM3 Hamiltonian, for which the Q 2 cum was about 0.937. The molecular weight (Mw) and energy of the lowest unoccupied molecular orbital (E LUMO ) were found to be main factors governing the log K OA .
Aerosol and Air Quality Research, 2017
Polybrominated diphenyl ethers (PBDEs) are used as flame retardants, but are of concern due to their potential health risks. PBDEs are ubiquitous in the environment and their occurrence in polar regions highlights the importance of atmospheric transport. As yet, most researches emphasized evaporative and fugitive releases of PBDEs during production, use and waste management phases. However, the recent studies have uncovered the importance of the combustion sources when considering the release of PBDEs into the atmosphere. Nevertheless, complete PBDE emission inventories are lacking, and no global PBDE emissions from combustion sources have been estimated. Therefore, this study estimated the global PBDE emissions from combustion sources and illegal open burning of waste electrical and electronic equipment (WEEE) and e-waste, as well as evaporative and fugitive releases from commercial PBDE mixtures. We found that combustion sources and illegal open burning of e-waste globally emit PBDEs at 6.75 and 0.255-5.56 tonnes year-1 , and are important PBDE emitters. The effectiveness of reducing human exposure to PBDEs will be minimized and delayed if mitigation of PBDE emissions from combustion sources is ignored. Control of PBDE emissions from combustion sources should be taken along with the ban of commercial PBDE mixtures.
Rapid Communications in Mass Spectrometry, 2006
Atmospheric pressure photoionization (APPI) was assessed for the mass spectrometric analysis of polybromodiphenyl ethers (PBDEs) on the basis of a set of 17 standard compounds. Positive and negative ionization modes were both investigated. M R. ions were formed under positive ion conditions whereas the negative ion mode yielded [M-BrþO] À ions. The behavior of these APPIproduced ions towards collisional activation was studied using an ion trap mass spectrometer. In positive ion mode, the loss of Br 2 was one of the major fragmentation pathways, and was favored for ortho-substituted PBDEs. Conversely, the loss of COBr. occurred only for non-ortho-substituted congeners. The collisional excitation of [M-BrþO] À ions in the ion trap also led to the loss of Br 2 , to the elimination of HBr, and to the formation of product ions by cleavage of the ether bond. The formation of para-quinone radical anions was observed for PBDEs ranging from penta-to heptacongeners, whereas brominated aromatic carbanions were formed preferentially for the most brominated PBDEs studied in this work (hepta-or deca-BDEs). M þ. ions did not undergo this fragmentation process.
Gas chromatography and mass spectrometry of methoxylated polybrominated diphenyl ethers (MeO-PBDEs)
Journal of Mass Spectrometry, 2006
Twenty-six methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were characterized by gas chromatography (GC) on four different GC columns with different lengths and polarities, as well as by mass spectrometry using three ionization techniques, electron ionization (EI), electron capture negative ionization (ECNI) and positive ion chemical ionization (PICI). MeO-PBDE congeners with similar retention times on a nonpolar GC column were separated when analyzed on a polar GC column. EI can be used to determine the position of the methoxy substituent (ortho, meta or para) relative to the diphenyl ether oxygen in the MeO-PBDEs. The PICI ionization technique is shown to be valuable to generate structural information of the MeO-PBDEs, i.e. the degree of bromination on both the methoxy-substituted ring and the entirely brominated phenyl ring can be obtained. This structure information can also be achieved for certain MeO-PBDEs with the methoxy group in ortho position to the diphenyl ether bond in ECNI mode. Like other brominated compounds ECNI is preferable when analyzing environmental samples for quantification of MeO-PBDEs because of the formation of bromide ions, which enables low detection limits.
Waste combustion as a source of ambient air polybrominated diphenylethers (PBDEs
Atmospheric Environment, 2011
The first comprehensive set of U.S. data on polybrominated diphenylether (PBDE) concentrations from municipal waste combustion (MWC), with more than 40 PBDE congeners reported, was compared to ambient air levels of PBDEs in the U.S. The PBDE profiles in the raw MWC flue gas reflected the historical production and usage pattern of PBDE-based flame retardants in North America, which favored Pentaand Deca-BDE formulations. The pattern of selected, routinely measured in the environment, PBDEs (TeBDE-47, PeBDE-99, PeBDE-100, HxBDE-153 and DcBDE-209) was similar in the MWC emissions and profiles most commonly reported for the U.S. atmosphere.
Environmental Health Perspectives, 2007
Polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental contaminants that are found in both abiotic and biotic environmental samples (Hites 2004; Streets et al. 2006). PBDEs are used as flame retardants; the three main commercial types of PBDE are penta-BDE, octa-BDE, and deca-BDE. DE-71, a widely used commercial penta-BDE product, is generally composed of 50-60% penta-BDE congeners, 24-38% tetra-BDE congeners, and 4-8% hexa-BDE congeners (Birnbaum and Staskal 2003). Since the 1970s, penta-BDE has been used as a flame retardant in polyurethane foam-containing consumer goods such as carpet padding, sofas, and mattresses; this flame retardant can account for up to 30% by weight of the foam (Hale et al. 2002). DE-71 also has minor uses in phenolic resins, polyesters, and epoxy. Despite its relatively small global production and usage compared with deca-BDE, the congeners in penta-BDE, such as 2,2´,4,4´-tetrabromodiphenyl ether (BDE-47), 2,2´,4,4´,5pentabromodiphenyl ether (BDE-99), and 2,2´,4,4´,5,5´-hexabromodiphenyl ether (BDE-153), are the most common PBDE congeners found in environmental samples, Materials and Methods Chemicals. We obtained commercial DE-71 from the Great Lakes Chemical Corporation (West Lafayette, IN). Dimethyl sulfoxide and β-estradiol-3-benzoate were purchased from Sigma Chemical Co. (St. Louis, MO), and corn oil was purchased from ICN Biomedicals (Aurora, OH). We purchased all of the neutral standards (
Analytical Chemistry, 2009
A total of 14 tetra-to deca-PBDE congeners were separated on a C 18 reversed phase liquid chromatographic column. PBDEs 47, 85, 99, 100, 153, 154, 183, 196, 197, 203, 206, 207, 208, and 209 were eluted using a gradient methanol/water/toluene mobile phase system at a flow rate of 0.5 mL min -1 . 13 C-BDE-47, 13 C-BDE-99, 13 C-BDE-153, BDE-128, and 13 C-BDE-209 were used as internal standards, while 13 C-BDE-100 was used as a syringe standard. Separated analytes were ionized using an atmospheric pressure photoionization (APPI) source equipped with a 10 eV krypton lamp and operated in negative ion mode. [M-Br + O]ions were monitored as precursor ions for all studied PBDEs, except for BDE-208 and BDE-209 which produced higher intensity at the [C 6 Br 5 O]ion cluster.