Octabromodiphenyl ether

Octabromodiphenyl ether
Other names OctaBDE, Octa-BDE
Identifiers
CAS number	32536-52-0
Properties
Molecular formula	C12H2Br8O
Molar mass	801.31 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
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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

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
	BDE-153	2,2′,4,4′,5,5′-hexa- bromodiphenyl ether	0.15–8.7 %
	BDE-154	2,2′,4,4′,5,6′-hexa- bromodiphenyl ether	0.04–1.1 %
	BDE-171	2,2′,3,3′,4,4′,6-hepta- bromodiphenyl ether	0.17–1.8 %
	BDE-180	2,2′,3,4,4′,5,5′-hepta- bromodiphenyl ether	n.d.–1.7 %
	BDE-183	2,2′,3,4,4′,5′,6-hepta- bromodiphenyl ether	13–42 %
	BDE-196	2,2′,3,3′,4,4′,5,6′-octa- bromodiphenyl ether	3.1–10.5 %
	BDE-197	2,2′,3,3′,4,4′,6,6′-octa- bromodiphenyl ether	11–22 %
	BDE-203	2,2′,3,4,4′,5,5′,6-octa- bromodiphenyl ether	4.4–8.1 %
	BDE-206	2,2′,3,3′,4,4′,5,5′,6-nona- bromodiphenyl ether	1.4–7.7 %
	BDE-207	2,2′,3,3′,4,4′,5,6,6′-nona- bromodiphenyl ether	11–12 %
	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

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

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

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

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

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.