Butane

Related Topics:
Butane,_Inguna

Butane
General
Molecular formula	C₄H₁₀
SMILES	CCCC
Molar mass	58.08 g/mol
Appearance	colorless gas
CAS number	^*
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
S-phrases	, ,
Flash point	−60 °C
Autoignition temperature	287 °C
Explosive limits	1.8–8.4%
Supplementary data page
Structure and properties	n, ε_r, 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) Chemical infobox

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.

References

Bond dissociation energies: Senosiain, J. P.; Han, J. H.; Musgrave, C. B.; Golden, D. M. Faraday Discussions (2001), vol. 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) Vol. 275, pp. 191 - 193.

External links

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Reactions and uses

See also

References

External links