2,4,6-tribromophenol

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Structural formula
Structural formula of 2,4,6-tribromophenol
General
Surname 2,4,6-tribromophenol
other names
  • Bromol
  • TBP
Molecular formula C 6 H 3 Br 3 O
Brief description

white to reddish-white solid

External identifiers / databases
CAS number 118-79-6
EC number 204-278-6
ECHA InfoCard 100.003.890
PubChem 1483
ChemSpider 1438
DrugBank DB02417
Wikidata Q209180
properties
Molar mass 330.79 g · mol -1
Physical state

firmly

density

2.55 g cm −3 (20 ° C)

Melting point

89-92 ° C

boiling point

244 ° C

pK s value

6.08

solubility

very bad in water (71 mg l −1 at 15 ° C)

safety instructions
GHS labeling of hazardous substances
07 - Warning 09 - Dangerous for the environment

Caution

H and P phrases H: 317-319-400
P: 273-280-305 + 351 + 338
Toxicological data

2000 mg kg −1 ( LD 50 ,  rat ,  oral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

2,4,6-Tribromophenol ( TBP ) is a chemical compound that belongs to both the phenols and the halogen aromatic compounds . The structure consists of a benzene ring with an attached hydroxy group  (-OH) and three bromine atoms  (-Br) as substituents . It will u. a. used as a flame retardant .

presentation

2,4,6-Tribromophenol 2 is produced by the direct bromination of phenol 1 with elemental bromine in the presence of potassium bromide . If bromine is used in excess, the 2,4,6-tribromophenol reacts to 2,4,4,6-tetrabromo-2,5-cyclohexadienone (old trivial name: tribromophenol bromine, melting point 124 ° C.). This secondary reaction can be reversed with hydrogen iodide .

Preparation of tribromophenol by bromination of phenol with elemental bromine

properties

2,4,6-tribromophenol forms whitish-pink scales that melt at 87–90 ° C. The boiling point is 282–290 ° C. Due to the −I effect of the bromine substituents, it has a higher acidity compared to phenol. The pK s value of 6.08 is therefore significantly lower (phenol: 9.99).

Reactions

In the nitration of 2,4,6-tribromophenol, the bromine atom is displaced by the nitro group at the para position, and 2,6-dibromo-4-nitrophenol is formed. However, if you start from the ethyl ether of 2,4,6-tribromophenol, the nitro group is added to the 3-position, so 1-ethoxy-2,4,6-tribromo-3-nitrobenzene is formed. Organisms metabolize 2,4,6-tribromophenol to 2,4,6-tribromanisole .

When cooking with zinc dust and glacial acetic acid , a bromine atom is split off from the ortho position, resulting in 2,4-dibromophenol .

Environmental relevance and dangers

In electronic waste an average concentration of 18 was in a 2011 study conducted  ppm found what the presence of TBP confirmed in electronic devices.

In 2012, 2,4,6-tribromophenol was included in the EU's ongoing action plan ( CoRAP ) in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation . The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. The reasons for the uptake of 2,4,6-tribromophenol were concerns about its classification as a CMR substance, high (aggregated) tonnage, high risk characterization ratio (RCR) and widespread use as well as the dangers arising from a possible assignment to the group of PBT / vPvB substances. The re-evaluation took place from 2012 and was carried out by Norway . A final report was then published.

Web links

Individual evidence

  1. ↑ a b c d e f g h Entry on 2,4,6-tribromophenol in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
  2. ^ Concise International Chemical Assessment Document (CICAD) for 2,4,6-Tribromophenol and other simple brominated phenols , accessed December 9, 2014.
  3. ↑ Data sheet 2,4,6-tribromophenol from Acros, accessed on June 11, 2010.
  4. ↑ Åke Bergman , Andreas Rydén, Robin J. Law, Jacob de Boer, Adrian Covaci, Mehran Alaee, Linda Birnbaum, Myrto Petreas, Martin Rose, Shinichi Sakai, Nele Van den Eede, Ike van der Veen: A novel abbreviation standard for organobromine , organochlorine and organophosphorus flame retardants and some characteristics of the chemicals . In: Environment International . tape 49 , 2012, p. 57–82 , doi : 10.1016 / j.envint.2012.08.003 , PMC 3483428 (free full text).
  5. ^ L. Gattermann , H. Wieland : The practice of organic chemists , 43rd edition, Walter de Gruyter , Berlin · New York 1982, ISBN 3-11-006654-8 , p. 230: "2,4,6-Tribromphenol ".
  6. ↑ JA Price: The Structure of Tribromophenol bromide , in: J. Am. Chem. Soc. 1955 , 77 , pp. 5436-5437; doi : 10.1021 / ja01625a081 .
  7. ^ HP Latscha, HA Klein, GW Linti: Analytical Chemistry: Chemistry-Basiswissen III , p. 287 ( limited preview in the Google book search).
  8. ↑ CRC Handbook of Tables for Organic Compound Identification , 3rd Edition, 1984, ISBN 0-8493-0303-6 .
  9. ↑ KJP Orton: The Nitration of s-Trihalogen Acetanilides , in: J. Chem. Soc., Transactions 1902 , 81 , pp. 501-502; doi : 10.1039 / CT9028100500 ; Full text .
  10. ^ University of Hohenheim: Halogenated Natural Products (HNPs) .
  11. ^ W. Suske: Polybrominated and still natural , in: Chemische Rundschau , No. 4, April 18, 2006, pp. 31–34; PDF .
  12. ^ Moritz Kohn, Julius Pfeifer: Dehalogenations of bromophenols. XXIV. Communication on bromophenols. In: Monthly magazine for chemistry. 48 (5-6), 1927, pp. 211-229, doi : 10.1007 / BF01518617 .
  13. ^ Ruedi Taverna, Rolf Gloor, Urs Maier, Markus Zennegg, Renato Figi, Edy Birchler: Material flows in Swiss electronic waste . Metals, non-metals, flame retardants and polychlorinated biphenyls in small electrical and electronic devices . Federal Office for the Environment , Bern 2017. Environmental status No. 1717: 164 p.
  14. ↑ European Chemicals Agency (ECHA): Substance Evaluation Conclusion and Evaluation Report
  15. ↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): 2,4,6-tribromophenol , accessed on March 26, 2019.