Boron tribromide
| Boron tribromide | |
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Boron tribromide |
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Other names
Tribromoborane |
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| Identifiers | |
| CAS number | 10294-33-4  |
| PubChem | 25134 |
| ChemSpider | 16787736 |
| EC number | 233-657-9 |
| UN number | 2692 |
| RTECS number | ED7400000 |
| Jmol-3D images | Image 1 Image 2 |
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| 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 |
| Viscosity | 7.31 x 10-4 Pa s (20 °C) |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
-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 Within the European Union, the following additional hazard statement (EUH014) must also be displayed on labelling: Reacts violently with water. |
| 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
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| Flash point | -18 °C |
| Related compounds | |
| Related compounds | Boron trifluoride Boron trichloride Boron triiodide |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Boron tribromide, BBr3, is a colorless, fuming liquid compound containing boron and bromine. It is decomposed by water and alcohols.[2]
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Chemical properties [edit]
Boron tribromide is commercially available and is a strong Lewis acid.
It is an excellent demethylating or dealkylating agent for the cleavage of ethers, also with subsequent cyclization, often in the production of pharmaceuticals.[3]
The mechanism of ether dealkylation proceeds via the formation of a complex between the boron center and the ether oxygen followed by the elimination of an alkyl bromide to yield a dibromo(organo)borane. The dibromo(organo)borane can then undergo hydrolysis to give a hydroxyl group, boric acid, and hydrogen bromide as products.[4]
- ROR + BBr3 → RO+(-BBr3)R → ROBBr2 + RBr
- ROBBr2 + 3H2O → ROH + B(OH)3 + 2HBr
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.[5] Boron tribromide also mediates the dealkylation of aryl alkyl ethers.
Synthesis [edit]
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 [edit]
The first synthesis was done by M. Poggiale in 1846 by reacting boron trioxide with carbon and bromine at high temperatures:[6]
- 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:[7]
- 2 B + 3 Br2 → 2 BBr3
Applications [edit]
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This section does not cite any references or sources. (March 2013) |
Pharmaceutical Manufacturing
Image Processing
Semiconductor Doping
Semiconductor Plasma Etching
Photovoltaic Manufacturing
Reagent for Various Chemical Processes
See also [edit]
References [edit]
- ^ 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.
- ^ "Boron Tribromide". Toxicologic Review of Selected Chemicals. National Institute for Occupational Safety and Health.
- ^ Doyagüez, E. G. (2005). "Boron Tribromide" (pdf). Synlett 2005 (10): 1636–1637. doi:10.1055/s-2005-868513.
- ^ McOmie, J. F. W.; Watts, M. L.; West, D. E. (1968). "Demethylation of Aryl Methyl Ethers by Boron Tribromide". Tetrahedron 24 (5): 2289–2292. doi:10.1016/0040-4020(68)88130-X.
- ^ Komatsu, Y.; Mihailetchi, V. D.; Geerligs, L. J.; van Dijk, B.; Rem, J. B.; Harris, M. (2009). "Homogeneous p+ emitter diffused using borontribromide for record 16.4% screen-printed large area n-type mc-Si solar cell". Solar Energy Materials and Solar Cells 93 (6–7): 750–752. doi:10.1016/j.solmat.2008.09.019.
- ^ Poggiale, M. (1846). "Nouveau composé de brome et de bore, ou acide bromoborique et bromoborate d'ammoniaque". Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences 22: 124–130.
- ^ Wöhler, F.; Deville, H. E. S.-C. (1858). "Du Bore". Annales de Chimie et de Physique 52: 63–92.
Further reading [edit]
- Doyagüez, E. G. (2005). "Boron Tribromide" (pdf). Synlett 2005 (10): 1636–1637. doi:10.1055/s-2005-868513.
External links [edit]
- Boron Tribromide at The Periodic Table of Videos (University of Nottingham)
- "Material Safety Data Sheet – Boron tribromide". Fisher Science.
- US patent 2989375, May, F. H.; Bradford, J. L., "Production of Boron Tribromide", issued 1961-06-20, assigned to American Potash & Chemical
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