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BUTANE
| Butane |
  |
| General |
| Molecular formula |
C4H10 |
| SMILES |
CCCC |
| Molar mass |
58.08 g/mol |
| Appearance |
colorless gas |
| CAS number |
[106-97-8] |
| Properties |
| Density and phase |
2.52 g/l, gas (15 °C, 1 atm) |
| Solubility in water |
6.1 mg/100 ml (20 °C) |
| Melting point |
−138.3 °C (134.9 K) |
| Boiling point |
−0.5 °C (272.7 K) |
| Hazards |
| MSDS |
External MSDS |
| EU classification |
Highly flammable (F+) |
| NFPA 704 |
|
| R-phrases |
R12 |
| S-phrases |
S2, S9, S16 |
| Flash point |
−60 °C |
| Autoignition temperature |
287 °C |
| Explosive limits |
1.8–8.4% |
| Supplementary data page |
Structure and
properties |
n, εr, etc. |
Thermodynamic
data |
Phase behaviour
Solid, liquid, gas |
| Spectral data |
UV, IR, NMR, MS |
| Related compounds |
| Related alkanes |
Propane
Pentane |
| Related compounds |
Isobutane |
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references |
Butane, also called n-butane, is the unbranched alkane with four carbon atoms, CH3CH2CH2CH3. Butane is also used as a collective term for n-butane together with its only other isomer, isobutane (also called methylpropane), CH(CH3)3.
Butanes are highly flammable, colorless, easily liquefied gases. The name butane was derived by back-formation from the name of butyric acid.
Reactions and uses
When oxygen is plentiful, butane burns to form carbon dioxide and water vapor: When oxygen is limited, carbon (soot) or carbon monoxide may also be formed.
n-Butane is the feedstock for duPont's process for the preparation of maleic anhydride. The catalyst for this process has the approximate formula
-
- CH3CH2CH2CH3 + 3.5 O2 → C2H2(CO)2O + 4 H2O
Butane, like all hydrocarbons, undergoes free radical chlorination to give both 1-chloro- and 2-chlorobutanes, as well as more highly chlorinated derivatives. The relative rates of the chlorination is partially explained by the differing bond dissociation energies, 425 and 411 kJ/mol for the two types of C-H bonds. The two central carbon atoms have the slightly weaker C-H bonds.
Butane gas is sold bottled as a fuel for cooking and camping, in which case it is referred to commercially as LPG. It is also used as a petrol component, as a feedstock for the production of base petrochemicals in steam cracking, as fuel for cigarette lighters and as a propellant in aerosol sprays. Despite its flammability, very pure forms of butane are also occasionally used as a refrigerant in automobiles that are set up to use R-12, because R-12 is an ozone depleting halomethane.
See also
References
- Bond dissociation energies: Senosiain, J. P.; Han, J. H.; Musgrave, C. B.; Golden, D. M. Faraday Discussions 2001, 119, 173-189.
- Coulston, G. W.; Bare, S. R.; Kung, H.; Birkeland, K.; Bethke, G. K.; Harlow, R.; Herron, N.; Lee, P. L. "The Kinetic Significance of V5+ in n-Butane Oxidation Catalyzed by Vanadium Phosphates" Science 1997, 275, pp. 191 - 193.
External links
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