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]]