Boron tribromide

Boron tribromide
IUPAC name

Boron tribromide
Other names

Tribromoborane
Identifiers
CAS number 10294-33-4 Y
PubChem 25134
ChemSpider 16787736 Y
EC number 233-657-9
UN number 2692
RTECS number ED7400000
Jmol-3D images Image 1
Image 2
Properties
Molecular formula BBr3
Molar mass 250.52 g/mol
Appearance colorless to amber liquid
Density 2.643 g/cm3
Melting point

−46.3 °C, 227 K, -51 °F
Boiling point

91.3 °C, 364 K, 196 °F
Solubility in water reacts violently
Vapor pressure 7.2 kPa (20 °C)
Refractive index (nD) 1.00207
Thermochemistry
Std enthalpy of
formation ΔfHo298		 -0.8207 kJ/g
Specific heat capacity, C 0.2706 J/K
Hazards[1]
MSDS ICSC 0230
GHS pictograms
GHS signal word DANGER
GHS hazard statements H330, H300, H314 [note 1]
EU Index 005-003-00-0
EU classification Very toxic (T+)
Corrosive (C)
R-phrases R14, R26/28, R35
S-phrases (S1/2), S9, S26, S28, S36/37/39, S45
NFPA 704
0
3
2
W
Flash point -18 °C
Related compounds
Related compounds Boron trifluoride
Boron trichloride
Boron triiodide
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Boron tribromide, BBr3, is a colorless, fuming liquid compound[2] 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.[3]

Contents

Chemical properties

Boron tribromide is commercially available and is a strong Lewis acid. It is an excellent demethylating or dealkylating agent for ethers, often in the production of pharmaceuticals. Additionally, it also finds applications in olefin polymerization 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 in the manufacture of semiconductors.[4]

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:[5]

B2O3 + 3 C + 3 Br2 → 2 BBr3 + 3 CO

An improvement of this method was developed by F. Wöhler and Deville in 1857. By starting from amorphous boron the reaction temperatures are lower and no carbon monoxide is produced:[6]

2 B + 3 Br2 → 2 BBr3

See also

Applications

Pharmaceutical Manufacturing
Image Processing
Semiconductor Doping
Semiconductor Plasma Etching
Photovoltaic Manufacturing
Reagent for Various Chemical Processes.[7]

References

  1. ^ Index no. 005-003-00-0 of Annex VI, Part 3, to Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006. OJEU L353, 31.12.2008, pp 1–1355 at p 341.
  2. ^ National Institute for Occupational Safety and Health. Toxicologic Review of Selected Chemicals - 132: BORON TRIBROMIDE.
  3. ^ Vacwell Engineering Company v BHD Chemicals Ltd [1969] 1 A.C 191.
  4. ^ Boron Tribromide, Albemarle Corporation
  5. ^ M. Poggiale (1846). "Bore - Sur un nouveau composé de brome et de bore, l'acide bromoborique et le bromoborate d'ammoniaque". Comptes rendus hebdomadaires 22: 124–130. http://gallica.bnf.fr/ark:/12148/bpt6k29798/f128.table. 
  6. ^ F. Wöhler, H. E. S.-C. Deville (1858). "Du bore". Annales de chimie et de physique 52: 63–92. http://gallica.bnf.fr/ark:/12148/bpt6k347939/f62.table. 
  7. ^ Air Liquide Electronics U.S. LP [1]
  1. ^ Within the European Union, the following additional hazard statement (EUH014) must also be displayed on labelling: Reacts violently with water.

Further reading

External links