Polybrominated biphenyls

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Polybrominated biphenyls [PBB congeners]
(m = 0, 1, 2, 3, 4 or 5;
n = 0, 1, 2, 3, 4 or 5)

Polybrominated biphenyls ( PBB ) are a class of compounds in which several hydrogen atoms are replaced by bromine in a bicyclic system . They are characterized by high chemical stability , hardly biodegradable and accumulate in adipose tissue.

Manufacturing

PBB are produced by bromination of biphenyl using aluminum chloride (AlCl 3 ) as a catalyst .

properties

PBB have a biphenyl backbone (two benzene rings linked by a single bond ) on which one or more hydrogen atoms have been replaced by bromine atoms . The general empirical formula is therefore C 12 H 10 − x Br x . There are 209 different congeners , but only a few of them are found in commercial products (e.g. bromadiolone ):

Overview of the congeners with the same degree of bromination
PBB homolog CAS number Br substituents Number of congeners
Monobromobiphenyl
2-bromobiphenyl
3-bromobiphenyl
4-bromobiphenyl 		26264-10-8
2052-07-5
2113-57-7
92-66-0 		1 3
Dibromobiphenyl 27479-65-8
92-86-4 (4,4′-DBBP) 		2 12
Tribromobiphenyl 51202-79-0 3 24
Tetrabromobiphenyl 40088-45-7 4th 42
Pentabromobiphenyl 56307-79-0 5 46
Hexabromobiphenyl 36355-01-8 6th 42
Heptabromobiphenyl 6355-01-8 7th 24
Octabromobiphenyl 27858-07-7 8th 12
Nonabromobiphenyl
2,2 ', 3,3', 4,4 ', 5,5', 6
2,2 ', 3,3', 4,4 ', 5,6,6'
2,2 ', 3, 3 ', 4.5.5', 6.6 ' 		27753-52-2
69278-62-2
119264-62-9
119264-63-0 		9 3
Decabromobiphenyl 13654-09-6 10 1

use

PBB are used as flame retardants and as plasticizers in plastics . They serve as substitutes for polychlorinated biphenyls (PCB).

toxicology

PBB are suspected of being toxic , carcinogenic and damaging to the liver . In addition, toxic properties with consequences such as memory and muscle weakness and immune deficiencies are suspected.

Application prohibitions

Since July 1, 2006, according to the Electrical and Electronic Equipment Act (ElektroG of March 16, 2005) and EU Regulation 2002/95 / EC ( RoHS ), it has been prohibited to put new electrical and electronic devices on the market that contain more than 0, Contains 1 percent by weight of PBB per homogeneous material.

See also

literature

Individual evidence

  1. ^ Agency for Toxic Substances and Disease Registry: Toxicological Profile for Polybrominated Biphenyls , 2004.