Hexabromocyclododecane

Suggested formulations for various polymers using hexabromocyclododecane (HBCD), a brominated aHphatic a chlorinated paraffin, ie, a chlorinated aHphatic and decabromodiphenyl oxide, a brominated aromatic, are shown in Tables 2—4. These suggested formulations may not be strictiy comparable because of differences in the nature of the base resins. However, the suggestions are specific to a given UL-94 rating. 

Phosphonium Salt—Urea Precondensate. A combination approach for producing flame-retardant cotton-synthetic blends has been developed based on the use of a phosphonium salt—urea precondensate (145). The precondensate is appUed to the blend fabric from aqueous solution. The fabric is dried, cured with ammonia gas, and then oxidized. This forms a flame-resistant polymer on and in the cotton fibers of the component. The synthetic component is then treated with either a cycUc phosphonate ester such as Antiblaze 19/ 19T, or hexabromocyclododecane. The result is a blended textile with good flame resistance. Another patent has appeared in which various modifications of the original process have been claimed (146). Although a few finishers have begun to use this process on blended textiles, it is too early to judge its impact on the industry. 

Hexabromocyclododecane (HBCD) is prepared by the bromination of lZ,5E,9E-cyclododecatriene (CDT). The term "HBCD" will be used here to denote the commercial product containing various isomer compositions. Bromination of CDT leads to three isomers, HBCD-1 (y), HBCD-2 (P) and HBCD-3(a). All three isomers (Fig. 1) were isolated and fully identified (refs. 1,2). 

Dissolution (toluene)/precipitation (methanol) of EPS beads (atactic PS foams with ca. 2wt.% HBCD and BaSCL) with TLC separation and IR identification allowed detection of hexabromocyclododecane for quantification XRF analysis (Br) was used [629]. Disso-lution/precipitation of PS/lubricants with evaporation to dryness and redissolution was followed by FT1R analysis [106],... 

BFRs are one of the last classes of halogenated compounds that are still being produced worldwide and used in high quantities in many applications. In order to meet fire safety regulations, flame retardants (FRs) are applied to combustible materials such as polymers, plastics, wood, paper, and textiles. Approximately 25% of all FRs contain bromine as the active ingredient. More than 80 different aliphatic, cyclo-aliphatic, aromatic, and polymeric compounds are used as BFRs. BFRs, such as polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA), have been used in different consumer products in large quantities, and consequently they were detected in the environment, biota, and even in human samples [26, 27]. 

Examples of additives and polymer substrates which could react via [1) would be chlorinated paraffin waxes, hexabromocyclododecane (HBCD) and poly(vinylchloride) or poly(vinylbromide). 

Eljarrat E, De La Cal A, Raldua D, Duran C, Barcelo D (2004) Occurrence and bioavailability of polybrominated diphenyl ethers and hexabromocyclododecane in sediment and fish from the Cinca River, a tributary of the Ebro River (Spain). Environ Sci Technol 38 2603-2608... 

Fig. 4 Scientific studies in sediments. HBCD hexabromocyclododecane PCBs polychlorinated biphenyls OCs organochlorine pesticides PCN polychlorinated naphthalene DDTs dichloro diphenyl trichloroethane...

Fig. 5 Scientific studies in biota. DDTs dichloro diphenyl trichloroethane HCB hexachlorobenzene HCHs hexachlorocyclohexanes OCs organochlorine pesticides OPs phosphorate pesticides PCBs polychlorinated biphenyls HBCD hexabromocyclododecane...

Keywords Bioaccumulation, Bioavailability, Brominated flame retardants, Hexabromocyclododecane, Polybrominated diphenyl ether... 

Sellstriim U, Kierkegaard A, de Wit C, Jansson B (1998) Polybrominated diphenyl ethers and hexabromocyclododecane in sediment and fish from a Swedish river. Environ Toxicol Chem 17 1065-1072... 

Hexaammineplatinum(IV), effective atomic number of noble gas, 7 590t Hexaaquachromium(III) ion, 6 533 Hexaaquamolybdenum(III) ion, 27 26-27 Hexaarylbiimidazolyl (HABI), piezochromic materials, 6 608 Hexabis(benzylthiomethyl)benzene, 24 180 Hexaborane(lO), physical properties of, 4 184t Hexaborane(12), 4 186 Hexabromocyclododecane, 22 467-468 formulations of, 22 460t physical properties of, 4 355t Hexabromocyclohexane, 3 602 Hexachlorobenzene, 3 602 Antoine constants, 6 215t physical and thermodynamic properties, 6 214t... 

HBCD hexabromocyclododecane, HCB hexachlorobenzene, p,p -DDT Dieldrin, 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane, p,p -DDE l,10-dichloro-2,20-bis(4-chlorophenyl) ethylene, p,p -DDD l,10-dichloro-2,20-bis-(4-chlorophenyl)ethane, PFOS perfluorooctane sulfonate, PFHS perfluorohexane sulfonate, PFBS perfluorobutane sulfonate... 

Due to their adverse health effects, several restrictions and bans have been imposed on the usage of polybrominated diphenyl ethers (PBDEs), namely the penta-, octa-, and deca-BDE formulations, in Europe, China, North America, and Japan (http //www. bsef.com). The restricted usage of these PBDEs increased the market demand for substitute brominated flame retardants (BERs) including hexabromocyclododecanes... 

Law K, Palace VP, Halldorson T, Danell R, Wautier K, Evans B, Alaee M, Marvin C, Tomy GT (2006) Dietary accumulation of Hexabromocyclododecane diastereoisomers in juvenile rainbow trout (Oncorhynchus mykiss) I biomaccumulation parameters and evidence of bioisomerization. Environ Toxicol Chem 25 1757-1761... 

Vorkamp K, Riget FR, Bossi R, Dietz R (2011) Temporal trends of hexabromocyclododecane, polybrominated diphenyl ethers and polychlorinated biphenyls in ringed seals from East Greenland. Environ Sci Technol 45 1243-1249... 

Covaci A, Gerecke AC, Law RJ, Voorspoels S, Kohler M, Heeb NV, Leslie H, Allchin CR, De Boer J (2006) Hexabromocyclododecanes (HBCDs) in the environment and humans a review. Environ Sci Technol 40 3679-3688... 

Roosens L, Abdallah MAE, Harrad S, Neels H, Covaci A (2009) Exposure to hexabromocyclododecanes (HBCDs) via dust ingestion, but not diet, correlates with concentrations in human serum preliminary results. Environ Health Perspect 117 1707-1712... 

Goscinny S, Vandevijvere S, Maleki M, Van Overmeire I, Windal I, Hanot V, Blaude MN, Vleminckx C, Van Loco J (2011) Dietary intake of hexabromocyclododecane diastereoisomers in the Belgian adult population. Chemosphere 84 279-288... 

---