Fluorosulfuric acid
Encyclopedia : F : FL : FLU : Fluorosulfuric acid
| Fluorosulfuric acid | |
|---|---|
| |
| General | |
| Other names | Fluorosulfonic acid, Fluorosulfuric acid, |
| Molecular formula | FSO3H. |
| Ho value | - 15.1 |
| Molar mass | 100.0645 g/mol |
| Appearance | Colorless, liquid. |
| CAS number | CAS=-->7789-21-1 |
| EINECS number | N/A |
| Properties | |
| Density and phase | 1.84 g/cm-3, liquid |
| Solubility in water | Soluble |
| Solubility in other solvents | ether, alcohols. |
| Melting point | -87.3 °C |
| Boiling point | 165.5 °C |
| Acidity (pKa) | -10 |
| Structure | |
| Molecular shape | tetrahedral |
| Dipole moment | N/A |
| Hazards | |
| MSDS | External MSDS |
| EU classification | 1777 Corrosive material |
| R-phrases | 20-35 |
| S-phrases | 26-45 |
| PEL (US, OSHA) | N/A |
| IDLH (US, NIOSH) | N/A |
| RTECS number | LP0715000 |
| Supplementary data page | |
| Structure & properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related compounds | Antimony pentafluoride CF3SO3H HF |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) [Chemical infoboxInfobox disclaimer and references] | |
Fluorosulfuric acid is FSO3H; it is one of the strongest acids commercially available in terms of acidic activity. It is also known by the alternative name, fluorosulfonic acid. The molecule is better described by the formula FSO2OH, which emphasizes its relationship to sulfuric acid, H2SO4. FSO3H is a tetrahedral molecule.
Chemical properties
Fluorosulfuric acid is a free-flowing colorless liquid. It is soluble in polar organic solvents (e.g. nitrobenzene, diethyl ether, acetic acid, and ethyl acetate), but poorly soluble in nonpolar solvents such as alkanes. Reflecting its strong acidity, it dissolves almost all organic compounds that are even weak proton acceptors [2]. FSO3H hydrolyzes slowly to HF and sulfuric acid. The related triflic acid CF3SO3H retains the high acidity of FSO3H but is hydrolytically stable.Production
Fluorosulfuric acid is prepared by the reaction of HF and sulfur trioxide- :SO3 + HF → FSO3H
Super-acids
FSO3H is one of the strongest known simple Brønsted acids, although recent work on carborane-based acids have led to still stronger acids[1]. It has an H0 value of −15.1 compared to −12 for sulfuric acid. The combination of FSO3H and the Lewis acid antimony pentafluoride produces "Magic acid," which is a far stronger protonating agent.Applications
FSO3H isomerizes alkanes and the alkylation of hydrocarbons with alkenes [4]. It can also be used as a laboratory fluorinating agent [3].Safety
Fluorosulfuric acid is considered to be highly toxic and corrosive. It hydrolyzes to release HF. Addition of water to FSO3H can be violent, similar to the addition of water to sulfuric acid.References
[1]M. Juhasz, S. Hoffmann, E. Stoyanov, K.-C. Kim, C. A. Reed, Angewandte Chemie International Edition 43 5352 - 5355 2004.[2] Encyclopedia of Reagents for Organic Synthesis 2001 John Wiley & Sons, Ltd
[3] Cotton, F.A.; Wilkinson, G. (1980) Advanced Inorganic Chemistry: A Comprehensive Text, 4th Edition, p.246, Wiley-Interscience Publications.
[4] Olah, G.; Farooq, O.; Husain, A.; Ding, N.; Trivedi, N.; Olah, J. (1991) Superacid FSO3H/HF-Catalyzed Butane Isomerisation. Catalysis Letters 10, 239-248.
External links
- For a full list of external links to MSDSs, spectroscopic data, commercial chemicals suppliers etc. for this compound, see [Chemical sources].
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.