Hypobromous acid

Summary

Hypobromous acid is an inorganic compound with chemical formula of HOBr. It is a weak, unstable acid. It is mainly produced and handled in an aqueous solution. It is generated both biologically and commercially as a disinfectant. Salts of hypobromite are rarely isolated as solids.

Hypobromous acid
Space-filling model of hypobromous acid
  Hydrogen, H
  Oxygen, O
  Bromine, Br
Names
IUPAC name
Hypobromous acid
Other names
  • Bromanol
  • Bromic(I) acid
  • Bromooxidane
  • Hydroxidobromine
Identifiers
  • 13517-11-8 checkY
3D model (JSmol)
  • Interactive image
ChEBI
  • CHEBI:29249 checkY
ChemSpider
  • 75379 checkY
ECHA InfoCard 100.119.006 Edit this at Wikidata
  • 83547
UNII
  • GHT9BV419J checkY
  • InChI=1S/BrHO/c1-2/h2H checkY
    Key: CUILPNURFADTPE-UHFFFAOYSA-N checkY
  • InChI=1S/BrHO/c1-2/h2H
    Key: CUILPNURFADTPE-UHFFFAOYSA-N
  • InChI=1/BrHO/c1-2/h2H
    Key: CUILPNURFADTPE-UHFFFAOYAL
  • OBr
Properties
HOBr
Molar mass 96.911 g·mol−1
Density 2.470 g/cm3
Boiling point 20–25 °C (68–77 °F; 293–298 K)
Acidity (pKa) 8.65
Conjugate base Hypobromite
Related compounds
Other cations
Sodium hypobromite
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Synthesis and properties edit

Addition of bromine to water gives hypobromous acid and hydrobromic acid (HBr(aq)) via a disproportionation reaction.

Br2 + H2O   HOBr + HBr

In nature, hypobromous acid is produced by bromoperoxidases, which are enzymes that catalyze the oxidation of bromide with hydrogen peroxide:[1][2]

Br + H2O2   HOBr + OH

Hypobromous acid has a pKa of 8.65 and is therefore only partially dissociated in water at pH 7. Like the acid, hypobromite salts are unstable and undergo a slow disproportionation reaction to yield the respective bromate and bromide salts.

3 BrO(aq) → 2 Br(aq) + BrO3(aq)

Its chemical and physical properties are similar to those of other hypohalites.

Uses edit

HOBr is used as a bleach, an oxidizer, a deodorant, and a disinfectant, due to its ability to kill the cells of many pathogens. The compound is generated in warm-blooded vertebrate organisms especially by eosinophils, which produce it by the action of eosinophil peroxidase, an enzyme which preferentially uses bromide.[3] Bromide is also used in hot tubs and spas as a germicidal agent, using the action of an oxidizing agent to generate hypobromite in a similar fashion to the peroxidase in eosinophils. It is especially effective when used in combination with its congener, hypochlorous acid.

References edit

  1. ^ Ximenes, V. F., Morgon, N. H., & de Souza, A. R. (2015). Hypobromous acid, a powerful endogenous electrophile: Experimental and theoretical studies. Journal of inorganic biochemistry, 146, 61-68.
  2. ^ Butler, Alison.; Walker, J. V. (1993). "Marine haloperoxidases". Chemical Reviews. 93 (5): 1937–1944. doi:10.1021/cr00021a014.
  3. ^ Mayeno, AN; Curran, AJ; Roberts, RL; Foote, CS (1989). "Eosinophils preferentially use bromide to generate halogenating agents". The Journal of Biological Chemistry. 264 (10): 5660–8. doi:10.1016/S0021-9258(18)83599-2. PMID 2538427. Archived from the original on 2009-05-26. Retrieved 2008-01-12.