Tetrabromobisphenol A

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Tetrabromobisphenol A
Tetrabromobisphenol A.svg
Identifiers
Abbreviations TBBPA, TBBP-A, TBBA
CAS number 79-94-7 YesY
ChEBI CHEBI:33217
Jmol-3D images Image 1
Properties
Molecular formula C15H12Br4O2
Molar mass 543.9 g·mol−1
Density 2,12 g·cm−3 (20 °C)[1]
Melting point 178 °C[1]
Boiling point 250 °C (decomposition)[1]
Hazards
R-phrases R50/53[1]
S-phrases S60 S61[1]
Main hazards N[1]
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

Tetrabromobisphenol A (TBBPA) is a brominated flame retardant.

Synthesis[edit]

TBBPA is a derivative of bisphenol A and is synthesized from this substance. Most commercial TBBPA products are of a relatively low purity, in fact containing a mixture of products brominated to varying extents. This is not generally considered to be a drawback, since in most applications of this substance (i.e. flame-retarding) it is the average %Br that is of importance. The mixture resulting from the bromination of bisphenol A is therefore not purified, allowing a more efficient, lower cost product.

Uses[edit]

TBBPA can be used as reactive and additive flame retardant. In the reactive application, TBBPA is bound chemically to the polymers. The main use are epoxy resins of printed circuit boards. As an additive flame retardant it is used in acrylonitrile butadiene styrene, which are used e.g. in TVs. The annual consumption consumption in Europe has been estimated as 6.200 tons in 2004.[2]

Relevance[edit]

TBBPA emits from different processes to the environment and can be found in trace concentration in the atmosphere, hydrosphere, soil, and sediments. It also occurs in sewage sludge and house dust.[3] TBBPA has been the subject of an eight year evaluation under the EU Risk Assessment procedure which reviewed over 460 studies. The Risk Assessment was published on the EU Official Journal in June 2008.[4] TBBPA will now go through REACH registration.

Toxicity[edit]

TBBPA is an endocrine disruptor and immunotoxicant. As an endocrine disruptor, TBBPA may interfere with both estrogens and androgens.[5] Further, TBBPA structurally mimics the thyroid hormone thyroxin (T4) and can bind more strongly to the transport protein transthyretin than T4 does, likely interfering with normal T4 activity. TBBPA likely also suppresses immune responses by inhibiting expression of CD25 receptors on T cells, preventing their activation, and by reducing natural killer cell activity.[6][7]

TBBPA degrades to bisphenol A and to TBBPA dimethyl ether, and experiments in zebrafish (Danio rerio) suggest that during development, TBBPA may be more toxic than either BPA or TBBPA dimethyl ether.[8]

References[edit]

  1. ^ a b c d e f Record of Tetrabromobisphenol A in the GESTIS Substance Database from the IFA, accessed on 2008/2/15
  2. ^ Draft EU Risk Assessment of 2,2′,6,6′- TETRABROMO-4,4′-ISOPRYOPYLIDENE DIPHENOL, Final Environmental Draft of June 2007
  3. ^ Kuch B, Körner W, Hagenmaier H (2001): Monitoring von bromierten Flammschutzmitteln in Fliessgewässern, Abwässern und Klärschlämmen in Baden-Württemberg. Umwelt und Gesundheit, Universität Tübingen.
  4. ^ TBBPA draft RAR
  5. ^ Shaw, S.; Blum, A.; Weber, R.; Kannan, K.; Rich, D.; Lucas, D.; Koshland, C.; Dobraca, D.; Hanson, S.; Birnbaum, L. (2010). "Halogenated flame retardants: do the fire safety benefits justify the risks?". Reviews on Environmental Health 25 (4): 261–305. doi:10.1515/REVEH.2010.25.4.261. PMID 21268442. 
  6. ^ Pullen, S; Boecker R.; Tiegs G (2003). "The flame retardants tetrabromobisphenol A and tetrabromobisphenol A–bisallylether suppress the induction of interleukin-2 receptor α chain (CD25) in murine splenocytes". Toxicology 184 (1): 11–22. doi:10.1016/S0300-483X(02)00442-0. 
  7. ^ Kibakaya, EC; Stephen K; Whalen MM (2009). "Tetrabromobisphenol A has immunosuppressive effects on human natural killer cells". Journal of Immunotoxicology 6 (4): 285–292. doi:10.3109/15476910903258260. 
  8. ^ McCormick, J; Paiva MS; Häggblom MM; Cooper KR; White LA (2010). "Embryonic exposure to tetrabromobisphenol A and its metabolites, bisphenol A and tetrabromobisphenol A dimethyl ether disrupts normal zebrafish (Danio rerio) development and matrix metalloproteinase expression". Aquatic Toxicology 100 (3): 255–262. doi:10.1016/j.aquatox.2010.07.019. PMID 20728951. 

External links[edit]