title: Methods for synthesis of nonabromodiphenyl ethers and a chloro-nonabromodiphenyl ether.
abstract: Polybrominated diphenyl ethers (PBDEs) have been used extensively as brominated flame retardants (BFRs) in textiles, upholstery and electronics. They are ubiquitous contaminants in wildlife and humans. A low concentration of nonabrominated diphenyl ethers (nonaBDEs) is present in commercial DecaBDE and they are also abiotic and biotic debromination products of decabromodiphenyl ether (BDE-209). The objective of the present work was to develop methods for synthesis of the three nonaBDEs, 2,2',3,3',4,4',5,5',6-nonabromodiphenyl ether (BDE-206), 2,2',3,3',4,4',5,6,6'-nonabromodiphenyl ether (BDE-207) and 2,2',3,3',4,5,5',6,6'-nonabromodiphenyl ether (BDE-208), with the intention of making them available as authentic standards for analytical, toxicological and stability studies, as well as studies regarding physical-chemical properties. Two methods were developed, one based on perbromination of phenoxyanilines and the other via reductive debromination of BDE-209 by sodium borohydride followed by chromatographic separation of the three nonaBDE isomers formed. An additional nonabrominated compound, 4'-chloro-2,2',3,3',4,5,5',6,6'-nonabromodiphenyl ether (Cl-BDE-208), was also synthesized in the present work. Cl-BDE-208, prepared by the perbromination of 4-chlorodiphenyl ether, may be used as an internal standard in analysis of highly brominated diphenyl ethers. BDE-206, BDE-207, BDE-208 and Cl-BDE-208 were characterized by 1H NMR, 13C NMR, electron ionization mass spectra and by their melting points. The structures of all three nonaBDEs have been characterized previously by X-ray crystallography.
authors.affiliation: Department of Environmental Chemistry, Stockholm University, Svante Arrhenius väg 12, SE-10691 Stockholm, Sweden. anna.christiansson@mk.su.se
authors.forename: Anna
authors.initials: A
authors.lastname: Christiansson
authors.forename: Daniel
authors.initials: D
authors.lastname: Teclechiel
authors.forename: Johan
authors.initials: J
authors.lastname: Eriksson
authors.forename: Ake
authors.initials: A
authors.lastname: Bergman
authors.forename: Göran
authors.initials: G
authors.lastname: Marsh
mesh_terms: D002625:Chemistry, Organic / Q000379:methods*; D018360:Crystallography, X-Ray; D005411:Flame Retardants / Q000138:chemical synthesis*; D055768:Halogenated Diphenyl Ethers; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010647:Phenyl Ethers / Q000138:chemical synthesis* / Q000737:chemistry; D011075:Polybrominated Biphenyls / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D005411:Flame Retardants; D055768:Halogenated Diphenyl Ethers; D010647:Phenyl Ethers; D011075:Polybrominated Biphenyls; C512044:2,2',3,3',4,4',5,5',6-nonabromodiphenyl ether; C512045:2,2',3,3',4,4',5,6,6'-nonabromodiphenyl ether; C010902:decabromobiphenyl ether; C512046:2,2',3,3',4,5,5',6,6'-nonabromodiphenyl ether