2,2 ,3,4,4 ,5 ,6-Heptabromodiphenyl ether

PBDEs are commercially available as three products penta-, octa-, and deca-BDE. All of these products are mixtures of several congeners. The compositions of these three products, as measured in our laboratory at Indiana University, are given in Table 4. The penta-product contains primarily 2,2/,4,4/-tetrabromodiphenyl ether (BDE-47), 2,2, 4,4, 5-pentabromodiphenyl ether (BDE-99), and 2,2, 4,4, 6-pentabromodiphcnyl ether (BDE-100) in a ratio of about 7 10 2. The octa-product contains primarily 2,2, 3,4,4, 5, 6-heptabromodiphenyl ether (BDE-183), 2,2, 3,3, 4,4, 5,6 -... 

COMPOUND NAME, PAGE 2,2, 3,4,4, 5, 6-Heptabromodiphenyl ether, 237 2,2, 4,4, 6-Pentabromodiphenyl ether, 234 Alkonox TNPP, 78 Alkanox TNPP, 79... 

The mixture of deca-BDE is composed almost exclusively of deca-BDE (BDE-209), with a rate of 97% or more and by 3% or less of nonabromodiphenyl ethers (nona-BDEs) and octa-BDEs. On the contrary, the commercial octa-BDE mixture usually contains between 10% and 12% hexabromodiphenyl ethers (hexa-BDEs), 44% of heptabromodiphenyl ethers (hepta-BDEs), between 31% and 35% of octa-BDEs, between 10% and 11% of nona-BDEs and <1% of deca-BDE [4]. The two compounds with a higher proportion in this mixture are, in first place, BDE-183 (2,2, 3,4,4, 5, 6-hepta-BDE) and then the BDE-153 (2,2, 4,4, 5,5 -hexa-BDE). In addition, the penta-BDE mixture, commercially known as DE-71, is primarily composed by tetrabromodiphenyl ethers (tetra-BDEs) (24—38%), penta-BDEs (50-60%) and hexa-BDEs (4-8%) being BDE-99 (2,2, 4,4, 5-penta-BDE) and BDE-47 (2,2, 4,4 -tetra-BDE) the main compounds of the mixture. Figure 1 shows different structures belonging to the three PBDE mixtures described. 

BDE-209 debromination during photolysis leads to the formation of less bro-minated congeners. The appearance of these photo-induced products is faster under UV irradiation than under sunlight. Figure 16.19 shows gas chromatograms over time of BDE-209 adsorbed on montmorillonite, during 101 days of irradiation by sunlight, and compared to a control held in darkness. Over time, the areas of peaks for nona-, octa- and heptabromodiphenyl ethers increased in the irradiated samples and remained at trace values in the dark control. Ahn et al. (2006) note a comparable but slower time trend for BDE-209 adsorbed on kaolinite. 

DeBDE=Decabromodiphenyl ether HpBDE=Heptabromodiphenyl ether HxBDE=Hexabromodiphenyl ether NoBDE=Nonabromodiphenyl ether OcBDE=Octabromodiphenyl ether PBDE=Polybrominated diphenyl ether PeBDE=Pentabromodiphenyl ether TeBDE=Tetrabromodiphenyl ether TrBDE=Tribromodiphenyl ether... 

The risk assessors note that the occurrence of Octa (and also Deca) appear to contradict the conventional wisdom that molecules such as decabromodiphenyl ether and to a lesser extent octa- and heptabromodiphenyl ether are too large to pass through biological membranes and should not accumulate in organisms. ... 

Representative Chemicals Heptabromodiphenyl-ether (HepBDE) Nonabromodiphenyl ether (NoBDE) Tetrabromodiphenyl ether (TeBDE) Elexabromodiphenyl ether (HeBDE) Octabro-modiphenyl Ether (OBDE) Pentabromodiphenyl ether (PeDBE) Decabromodiphenyl ether (De-BDE)... 

BDE-154 is a component of the commercially available octa-BDE, which is a complex mixture consisting typically of 0.5% pentabromodiphenyl ether isomers, 12% hexabromodiphenyl ether isomers, -45% heptabromodiphenyl ether isomers, 33% octaBDE isomers, 10% nonabromodiphenyl ether isomers and 0.7% decabromodiphenyl ether. It is used as a flame retardant in plastics for electrical and electronic equipment. 

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