Boron tribromide
3922915
217966607
2008-06-08T15:16:29Z
Elassint
4921533
{{Chembox new
| Name = Boron tribromide
| ImageFile = Boron-tribromide-3D-vdW.png
| ImageSize = 200px
| ImageName = Boron tribromide
| IUPACName = Boron tribromide
| Section1 = {{Chembox Identifiers
| CASNo = 10294-33-4
}}
| Section2 = {{Chembox Properties
| Formula = BBr<sub>3</sub>
| MolarMass = 250.537 g mol<sup>−1</sup>
| Density = 2.60 g cm<sup>−3</sup>
| Solvent = other solvents
| Solubility = Reacts violently
| MeltingPt = −46.3 °C −51.34 °F 227 K
| BoilingPtC = 91 }}
}}
'''Boron tribromide''', BBr<sub>3</sub>, is a liquid compound containing [[boron]] and [[bromine]]. It is usually made by heating [[boron trioxide]] with [[carbon]] in the presence of bromine: this generates free boron which reacts vigorously with the bromine. It is very volatile and fumes in air because it reacts vigorously with [[water]] to form [[boric acid]] and [[hydrogen bromide]].<ref>Vacwell Engineering Company v BHD Chemicals Ltd [1969] 1 A.C 191.</ref>
==Chemical properties==
Boron tribromide is commercially available and is a strong [[Lewis acid]]. It is an excellent demethylating or dealkylating agent for [[ether]]s, often in the production of [[medication|pharmaceuticals]]. Additionally, it also finds applications in [[olefin]] [[polymer]]ization and in [[Friedel-Crafts]]
chemistry as a [[Lewis acid]] [[catalyst]]. The electronics industry uses boron tribromide as a boron source in pre-deposition processes for [[doping (semiconductor)|doping]] in the manufacture of [[semiconductors]].<ref>[http://www.albemarle.com/TDS/Fine_chemistry_services/BC-0196_BORON_Tri-Bromide.pdf Boron Tribromide], Albemarle Corporation</ref>
==Synthesis==
The reaction of [[boron carbide]] with [[bromine]] at temperatures above 300 °C leads to the formation of boron tribromide. The product can be purified by vacuum [[distillation]].
==History==
The first synthesis was done by M. Poggiale in 1846 by reacting boron trioxide with carbon and bromine at high temperatures:<ref>{{cite journal
| title = Bore - Sur un nouveau composé de brome et de bore, l'acide bromoborique et le bromoborate d'ammoniaque
| author = M. Poggiale
| journal = Comptes rendus hebdomadaires
| volume = 22
| issue =
| pages = 124–130
| year = 1846
| url = http://gallica.bnf.fr/ark:/12148/bpt6k29798/f128.table
| doi = }}</ref>
:B<sub>2</sub>O<sub>3</sub> + 3 C + 3 Br<sub>2</sub> → 2 BBr<sub>3</sub> + 3 CO
An improvement of this method was developed by [[Friedrich Wöhler|F. Wöhler]] and [[Henri Etienne Sainte-Claire Deville| Deville]] in 1857. By starting from amorphous boron the reaction temperatures are lower and no carbon monoxide is produced:<ref>{{cite journal
| title = Du bore
| author = [[Friedrich Wöhler|F. Wöhler]], [[Henri Etienne Sainte-Claire Deville|H. E. S.-C. Deville]]
| journal = Annales de chimie et de physique
| volume = 52
| issue =
| pages = 63–92
| year = 1858
| url = http://gallica.bnf.fr/ark:/12148/bpt6k347939/f62.table
| doi = }}</ref>
:2 B + 3 Br<sub>2</sub> → 2 BBr<sub>3</sub>
==References==
<references/>
==External links==
* [http://www.google.de/patents?id=v3VTAAAAEBAJ&printsec=abstract&zoom=4&dq=%22Boron+tribromide%22+%22boron+carbide%22 1962 Patent on the production of boron tribromide]
[[Category:Boron compounds]]
[[Category:Bromine compounds]]
[[Category:Bromides]]
[[Category:Nonmetal halides]]
[[de:Bortribromid]]
[[fi:Booritribromidi]]
[[zh:三溴化硼]]