Octabromodiphenyl ether

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Octabromodiphenyl ether
BDE-203.svg
Identifiers
CAS number 32536-52-0
Properties
Molecular formula C12H2Br8O
Molar mass 801.38 g/mol
Appearance white solid
Density 2.9 g/cm3
Solubility in water not soluble
Hazards
R-phrases R61, R62
S-phrases S53, S45
Related compounds
Related polybrominated diphenyl ethers Decabromodiphenyl ether, Pentabromodiphenyl ether
Related compounds diphenyl ether
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Octabromodiphenyl ether (octaBDE, octa-BDE, OBDE, octa, octabromodiphenyl oxide, OBDPO) is a brominated flame retardant which belongs to the group of polybrominated diphenyl ethers (PBDEs).

Composition, uses, and production[edit]

Commercial octaBDE (also known as "Octabrom") is a technical mixture of different PBDE congeners having an average of 7.2 to 7.7 bromine atoms per molecule of diphenyl ether.[1] The predominant congeners in commercial octaBDE are those of heptabromodiphenyl ether and octaBDE.[1][2] The term octaBDE alone refers to isomers of octabromodiphenyl ether (PBDE congener numbers 194–205); the Infobox displays BDE-203 (2,2’,3,4,4’,5,5’,6-octabromodiphenyl ether).[3]

Composition of commercial octaBDE [4]
Structure Congener Name Fraction
Structure of BDE-153 BDE-153 2,2′,4,4′,5,5′-hexa-
bromodiphenyl ether
0.15–8.7%
Structure of BDE-154 BDE-154 2,2′,4,4′,5,6′-hexa-
bromodiphenyl ether
0.04–1.1%
Structure of BDE-171 BDE-171 2,2′,3,3′,4,4′,6-hepta-
bromodiphenyl ether
0.17–1.8%
Structure of BDE-180 BDE-180 2,2′,3,4,4′,5,5′-hepta-
bromodiphenyl ether
n.d.–1.7%
Structure of BDE-183 BDE-183 2,2′,3,4,4′,5′,6-hepta-
bromodiphenyl ether
13–42%
Structure of BDE-196 BDE-196 2,2′,3,3′,4,4′,5,6′-octa-
bromodiphenyl ether
3.1–10.5%
Structure of BDE-197 BDE-197 2,2′,3,3′,4,4′,6,6′-octa-
bromodiphenyl ether
11–22%
Structure of BDE-203 BDE-203 2,2′,3,4,4′,5,5′,6-octa-
bromodiphenyl ether
4.4–8.1%
Structure of BDE-206 BDE-206 2,2′,3,3′,4,4′,5,5′,6-nona-
bromodiphenyl ether
1.4–7.7%
Structure of BDE-207 BDE-207 2,2′,3,3′,4,4′,5,6,6′-nona-
bromodiphenyl ether
11–12%
Structure of BDE-209 BDE-209 Deca-
bromodiphenyl ether
1.3–50%

Only congeners with more than 1% listed.

OctaBDE is used in conjunction with antimony trioxide as a flame retardant in the housings of electrical and electronic equipment, mainly in the plastic acrylonitrile butadiene styrene, but also in high impact polystyrene, polybutylene terephthalate and polyamides.[5] Typically 12–15% of the weight of the final product will consist of octaBDE.[5]

The annual demand worldwide was estimated as 3,790 tonnes in 2001, of which Asia accounted for 1,500 tonnes, the Americas 1,500 tonnes, and Europe 610 tonnes.[6] The United Nations Environment Programme reports "Since 2004, it [octaBDE] is no longer produced in the EU, USA and the Pacific Rim and there is no information that indicates it is being produced in developing countries."[2]

Environmental chemistry[edit]

OctaBDE is released by different processes into the environment, such as emissions from the manufacture of octaBDE-containing products and from the products themselves.[2] Elevated concentrations can be found in air, water, soil, food, sediment, sludge, and dust.[2][7][8]

In the environment, "photolysis, anaerobic degradation and metabolism in biota" can cause debromination of octaBDE, which produces PBDEs with fewer bromine atoms "which may have higher toxicity and bioaccumulation potential."[2]

Exposures and health effects[edit]

OctaBDE may enter the body by ingestion or inhalation.[3] It is "stored mainly in body fat" and may stay in the body for years.[3] In an investigation carried out by the WWF, "the brominated flame retardant chemical (PBDE 153), which is a component of the penta- and octa- brominated diphenyl ether flame retardant products" was found in all blood samples of 14 ministers of health and environment of 13 European Union countries.[9]

The chemical has no proven health effects in humans; however, based on animal experiments, octaBDE may have effects on "the liver, thyroid, and neurobehavioral development."[3]

Governmental actions[edit]

The European Union has carried out a comprehensive risk assessment under the Existing Substances Regulation 793/93/EEC.[5] As a consequence, the EU has banned the use of octaBDE since 2004.[10]

In the United States, as of 2005, "no new manufacture or import of" pentaBDE and octaBDE "can occur... without first being subject to EPA [i.e., United States Environmental Protection Agency ] evaluation."[11] As of mid-2007, a total of eleven states in the U.S. had banned octaBDE.[12]

It has been proposed that octaBDE be added to the Stockholm Convention as it meets the criteria for the so-called persistent organic pollutants of persistence, bioaccumulation and toxicity.[2]

Alternatives[edit]

Alternatives to octaBDE include tetrabromobisphenol A, 1,2-bis (pentabromophenoxy) ethane, 1,2-bis(tribromophenoxy)ethane, triphenyl phosphate, resorcinol bis(diphenylphosphate), and brominated polystyrene; however, for each of these "the existing data on toxicological and ecotoxicological effects are fewer than for octabromodiphenyl ether."[13]

References[edit]

  1. ^ a b United States Patent and Trademark Office. Melting point enhancement of partially brominated diphenyl oxide mixtures. US Patent 5,000,879 issued on March 19, 1991.
  2. ^ a b c d e f Ad hoc working group on C-Octabromodiphenyl ether under the Persistent Organic Pollutants Review Committee of the Stockholm Convention. Draft risk profile: commercial octabromodiphenyl ether. United Nations Environment Programme, August 2007.
  3. ^ a b c d Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polybrominated Biphenyls and Polybrominated Diphenyl Ethers (PBBs and PBDEs). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, September 2004.
  4. ^ M. J. La Guardia, R. C. Hale, E. Harvey: Detailed Polybrominated Diphenyl Ether (PBDE) Congener Composition of the Widely Used Penta-, Octa-, and Deca-PBDE Technical Flame-retardant Mixtures, Environ. Sci. Technol., 2006, 40, 6247–6254, doi:10.1021/es060630m.
  5. ^ a b c European Union risk assessment report. Diphenyl ether, octabromo derivative. Luxembourg: Office for Official Publications of the European Communities, 2003. Publication EUR 20403 EN.
  6. ^ Bromine Science and Environmental Forum. Major Brominated Flame Retardants Volume Estimates: Total Market Demand By Region in 2001. 21 January 2003.
  7. ^ Hale RC, La Guardia MJ, Harvey E, Gaylor MO, Mainor TM (2006): Brominated flame retardant concentrations and trends in abiotic media. Chemosphere. 64(2):181-6. doi:10.1016/j.chemosphere.2005.12.006 PMID 16434082
  8. ^ Stapleton, Heather M., et al. Polybrominated Diphenyl Ethers in House Dust and Clothes Dryer Lint. Environmental Science & Technology 39(4), 925-931, 2005.
  9. ^ WWF Detox Campaign. Bad Blood? A Survey of Chemicals in the Blood of European Ministers. October 2004.
  10. ^ Directive 2003/11/Ec of the European Parliament and of the Council of 6 February 2003 amending for the 24th time Council Directive 76/769/EEC relating to restrictions on the marketing and use of certain dangerous substances and preparations (pentabromodiphenyl ether, octabromodiphenyl ether). Official Journal of the European Union 15.2.2003.
  11. ^ U.S. Environmental Protection Agency. Polybrominated diphenylethers (PBDEs). "Last updated on Thursday, August 2nd, 2007." Accessed 2007-10-26.
  12. ^ Maine Joins Washington, Bans PBDEs. Washington, DC: National Caucus of Environmental Legislators, June 18, 2007.
  13. ^ Risk & Policy Analysts Limited. Octabromodiphenyl Ether. Risk Reduction Strategy and Analysis of Advantages and Drawbacks. Final Report. Prepared for Department for Environment, Food and Rural Affairs, United Kingdom, June 2002.