Poly bromination

Morris PJ, JF Quensen III, JM Tiedje, SA Boyd (1993) An assessment of the reductive debromination of poly-brominated biphenyls in the Pine River reservoir. Environ Sci Technol 27 1580-1586. 

Chemicals that possess a common structural feature are called congeners. Some common examples are polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), poly-brominated diphenylethers (PBDE) and chlorofluorocarbons (CFC). The common features... 

McCormack KM, Hook JB. 1982. Effects of lactation and nursing on tissue concentrations of poly brominated biphenyls and on microsomal enzyme activity in mammary gland and liver in maternal rats. EnvironRes 27 110-117. 

To explore the geographical distribution and temporal trends of poly-brominated diphenyl ethers (PBDEs) in the Great Lakes in more detail, lake trout from Lakes Superior, Michigan, Huron, and Ontario and walleye from Lake Erie, collected during the period of 1980-2000, were analyzed by Zhu and Hites [19]. The concentrations of fifteen PBDE congeners were de-... 

Table 9 shows that there are reasonably good data available for the poly-brominated diphenyl ethers (PBDEs), but there is much less information for the other BFRs. While the polybrominated biphenyls (PBBs) are no longer in production or use, it is clear that these compounds are persistent in the environment and in people thus, it would be prudent to continue to monitor the concentrations of these compounds in (at least) the sediment and fishes of the lakes. The other BFRs (HBCD, TBE, and PEB) are not currently abundant in the lakes, but the likelihood of their increased use in the future suggests that they too should be monitored in the sediment and fishes of the lakes. Of course, the... 

New Hampshire Developing public-health laboratory capacity to biomonitor for arsenic, mercury, phthalates, poly-brominated diphenyl ethers and planning pilot studies to estimate body burden of environmental toxicants using newly developed biomonitoring analytic methods (CDC 2005). 

Darnerud, P.O., Eriksen, G.S., Johannesson, T., Larsen, P.B., Viluksela, M., 2001. Poly-brominated diphenyl ethers Occurrence, dietary exposure, and toxicology. Environ. Health Perspect. 109, 49-68. 

Bocio, A., Llobet, J.M., Domingo, J.L., Corbella, J., Teixido, A., Casas, C., 2003. Poly-brominated diphenyl ethers (PBDEs) in foodstuffs Human exposure through the diet. J. Agric. Food Chem. 51, 3191-3195. 

International Agency for Research on Cancer, Polychlorinated Biphenyls and Poly-brominated Biphenyls, Vol. 18 October, 1978. 

The Directive of the European Parliament and of the Council 2002/95/EC on the Restriction of the Use of certain Hazardous Substances in Electrical and Electronic Equipment (RoHS) was put into effect on July 1, 2006.75 76 It states that Member States shall ensure that new electrical and electronic equipment (EEE) put on the market shall not contain more than 0.1% of Pb, Hg, Cd, Cr(VI), poly-brominated biphenyls (PBBs), PBDEs, or 0.01% Cr(VI). All other flame-retardants are compliant with the provisions of the RoHS Directive and can be used in EEE. 

Ter Schure, A. F. H., Larsson, R, Agrell, C., Boon, J. P. (2004) Atmospheric transport of poly-brominated diphenyl ethers and polychlorinated biphenyls to the Baltic Sea. Environ. Sci. Technol., 38 1282-1287. 

In response to the continuing discovery of the persistence, bioaccumulative properties, and toxicity of POPs, regional, national and international policies ban the intentional production of compounds, such as polychlorinated biphenyls (PCBs), several organochlo-rine pesticides, such as mirex and dieldrin, and the brominated flame retardants poly-brominated diphenyl ethers (penta-BDE and octa-BDE, and most recently, deca-BDE). Policies and programs have also targeted the unintentional production and release of POPs such as polychlorinated dibenzodioxins and furans (PCDD/Fs). Evidence of the success of these policies has been seen in immediate reductions of air concentrations, followed by declining concentrations in water bodies, soils, biota and our food supplies... 

Gobas et al. [30] in 1989 investigated the bioconcentration potential of polychlorinated biphenyls (PCBs), polybrominated benzenes (PBBzs) and poly-brominated biphenyls (PBBs), and other super-hydrophobic chemicals, such as decachlorobiphenyl and Mirex. These authors also pointed out the importance of bioavailability for bio concentration of super-hydrophobic chemicals. Their study showed that the bioavailable fraction of the super-hydrophobic chemical decachlorobiphenyl can be as low as 3 % and of Mirex can be as low as 2.2 %. For decachlorobiphenyl, a BCF was found that was one to two orders of magnitude lower than the true BCF. 

No matter the source, flame retardants, especially the poly brominated diphenyl ethers (PBDE s), are coming under scrutiny because they are persistent organic pollutants (POPs). They are appearing in human samples, most notably serum, adipose fat tissue and breast milk. PBDE s are also under investigation as potential endocrine mimickers or endocrine disrupters. As a result, PBDE s are the most highly regulated flame retardants. Their environmental fate will continue to be a topic of research for years to come. 

Polybrominated Biphenyls (PBBs) and Poly brominated Diphenyl Ethers (PBDEs)... 

Stross JK, Smokier IA, Isbister J, et al The human health effects of exposure to poly-brominated biphenyls. Toxicol Appl Pharmacol 58 145-150, 1981 Tilson HA, Harry GJ Developmental neurotoxicology of polychlorinated biphenyls and related compounds, in The Vulnerable Brain and Environmental Risks, Vol 3 Toxins in Air and Water. Edited by Isaacson RL, Jensen KF. New York, Plenum, 1994, pp 267-279... 

Use of some of the flame retardants, particularly brominated ones (PBDEs, or poly-brominated diphenyl esters), was prohibited by European Union Risk Assessment program. Among them were pentabromodiphenyl ether (pentaBDE), which was used primarily in polyurethane foam, and octabromodiphenyl ether (octaBDE), used mainly in electrical and electronic equipment and automobiles (both were prohibited by EU in August, 2004). In the United States, production of pentaBDE was ceased in 2004 and its mannfacture and import into the United States is prohibited. Octa-BDE was schednled to be prohibited in 2006 in a number of states in the United States... 

Direct photoreaction (eq 4) is important only for halocarbons (e.g., aromatic compounds) that significantly absorb radiation at wavelengths >295 nm, the cutoff for solar spectral irradiance at the earths surface. Because saturated chlorinated and fluorinated organic compounds, including methylchloroform and chlorofluorocarbons, absorb solar radiation very weakly, their direct photoreaction is very slow in the sea and in fresh waters. As discussed in a later section, photoreactions of these compounds may be accelerated by sorption and indirect photoreactions in natural waters. Saturated and olefinic poly-brominated and iodinated organic compounds have long absorption tails that extend beyond 295 nm. Direct photoreaction of such compounds in aquatic environments may be significant. 

Covad, A., Voorspoels, S., and de Boer, J., Determination of brominated flame retardants, with emphasis on poly brominated diphenyl ethers in environmental and human samples. Environ. Int., 29, 735-756, 2003. 

The European Union has taken the lead in restricting the use of some hazardous materials in the manufacture of electrical and electronic hardware. The program, referred to as Restriction of Hazardous Substances (RoHS), applies to all electrical and electronic products produced in Europe and products imported from other countries, thus has very broad application. The regulations put into force on July 1, 2006, apply to lead, cadmium, mercury, hexavalent chromium (Cr ), poly-brominated biphenyl (PBB), and polybrominated diphenyl ether (PBDE). The RoHS guideline document specifies 0.1% or 1,000 ppm as the maximum amount permitted for lead, mercury, Cr" " , PBB, and PBDE and 0.01% or 100 ppm for cadmium. The document also describes guidelines for sample preparation and analyses of the restricted materials. 

Triarylamines attracted considerable interest because of their potential as novel organic electronic materials [113-115]. Hartwig et al. [116] demonstrated tlie potential of P(tBu)3 (26) or DPPF (9) for such applications in the synthesis of dendrimeric triarylamines. Hole-transporting organic materials were synthesized from poly-brominated arenes and diarylamines using only 0.025 mol% of Pd(OAc)2/P(fBu)3 (26) (Scheme 13.68) [117]. 

Many workshops and conferences on the bromine compounds have been held under auspices of govemment/nongovemmental organizations and industry (examples References 158-160). Concern has lately focused on the lower brominated diphenyl ethers (such as penta-) which are detected widely in the environment. In a review, Dutch researchers conclude that the toxicity mechanism of poly-brominated diphenyl ethers is the same as that of the dioxins, and, although the present concentrations are not a large risk, these ethers are accumulative. Decabromodiphenyl oxide is less toxic than the less-brominated congeners, and its absorption from the gastrointestinal tract is low. 

Maruyama H, Homma K, Wada A, Shiokawa Y. The rapid analysis of PBDEs (poly brominated diphenyl ethers) utilizing the ion attachment mass spectrometry. Organohalogen Compd. 2007 69 2767-68. 

Effective use can sometimes be made of removable blocking groups on the ring. Suppose you are set the task of making pure < -bromophenol. Simple bromination of phenol will fail because of the dominant formation of the para isomer or of poly-brominated compounds (Fig. 14.90). A solution to this problem is first to sulfonate... 

Luyk [251] has examined formation of poly-brominated dibenzo-/ -dioxins (PBDD) and diben-zofurans (PBDF) during thermal processing of polymers containing polybrominated diphenyl ethers. The formation of PBDDs and PBDFs is a result of thermal and mechanical stress in the melt phase or condensed phase. The yield depends on temperature... 

Some PBBs are considered possible precursors of toxic poly-brominated dibenzo-p-dioxins (12-138) and dibenzofurans (12-139), which are formed during combustion. The formation of degradation products of PBBs depends generally on the temperature, the amount of oxygen present and certain other factors. A study of the pyrolysis of the commercial mixture FireMaster BP-6 in the absence of oxygen at 600-900 °C showed the formation of bromobenzenes and lower brominated biphenyls, but polybromi-nated furans did not result. Pyrolysis in the presence of oxygen at 700-900 °C, however, yielded di- to heptabromodibenzofurans. 

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