Boron tribromide
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| Names | |
|---|---|
| IUPAC name
Boron tribromide
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| Other names
Tribromoborane
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.030.585 |
| EC Number |
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PubChem CID
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| RTECS number |
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| UN number | 2692 |
CompTox Dashboard (EPA)
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| Properties | |
| BBr3 | |
| Molar mass | 250.52 g/mol |
| Appearance | colorless to amber liquid |
| Density | 2.643 g/cm3 |
| Melting point | −46.3 °C (−51.3 °F; 226.8 K) |
| Boiling point | 91.3 °C (196.3 °F; 364.4 K) |
| reacts violently | |
| Vapor pressure | 7.2 kPa (20 °C) |
Refractive index (nD)
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1.00207 |
| Thermochemistry | |
Heat capacity (C)
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0.2706 J/K |
Std enthalpy of
formation (ΔfH⦵298) |
-0.8207 kJ/g |
| Hazards | |
| GHS labelling: | |
 
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| Danger | |
| H300, H314, H330 [note 1] | |
| NFPA 704 (fire diamond) | |
| Flash point | -18 °C |
| 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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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]
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
- ^ 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.
- ^ National Institute for Occupational Safety and Health. Toxicologic Review of Selected Chemicals - 132: BORON TRIBROMIDE.
- ^ Vacwell Engineering Company v BHD Chemicals Ltd [1969] 1 A.C 191.
- ^ Boron Tribromide, Albemarle Corporation
- ^ 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.
- ^ F. Wöhler, H. E. S.-C. Deville (1858). "Du bore". Annales de chimie et de physique. 52: 63–92.
- ^ Air Liquide Electronics U.S. LP Boron Tribromide ( BBr3 )
- ^ Within the European Union, the following additional hazard statement (EUH014) must also be displayed on labelling: Reacts violently with water.
Further reading
- Doyagüez, Elisa García (2005). "Boron Tribromide". Synlett: 1636. doi:10.1055/s-2005-868513.