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Template:Chembox E numberTemplate:Chembox SolubilityInWaterTemplate:Chembox SDS
IUPAC name Isobutane
Other names 2-Methylpropane
3D model (JSmol)
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Molar mass 58.12 g·mol−1
Appearance colorless gas
Density 2.51 g/l, gas (15 °C, 1 atm);593.4 kg · m-3, liquid
Melting point
Boiling point
EU classification {{{value}}}
R-phrases R12
S-phrases (S2), S9, S16
Flash point {{{value}}}
Explosive limits 1.8–8.4%
Related compounds
Supplementary data page
Structure and
n, εr, etc.
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Isobutane, also known as methylpropane or 2-methylpropane, is an alkane, isomeric with butane. Recent concerns with depletion of the ozone layer by freon gases have led to increased use of isobutane as a gas for refrigeration systems, especially in domestic refrigerators and freezers, and as a propellant in aerosol sprays. When used as a refrigerant or a propellant, isobutane is also known as R-600a. It is used as a feedstock in the petrochemical industry, for example in the synthesis of isooctane.[1]


Structures of the two isomers of butane

Isobutane is the trivial name retained by the International Union of Pure and Applied Chemistry (IUPAC) in its 1993 Recommendations for the Nomenclature of Organic Chemistry.[2]

Methylpropane is the systematic name. The substituent number (2-) is unnecessary because there is no isomer of this molecule with methylpropane as part of its name.


  1. Patent Watch, July 31, 2006.
  2. Panico, R.; & Powell, W. H. (Eds.) (1994). A Guide to IUPAC Nomenclature of Organic Compounds 1993. Oxford: Blackwell Science. ISBN 0-632-03488-2.

External links

de:Isobutan el:Ισοβουτάνιο it:Isobutano hu:Izobután nl:Methylpropaan fi:Isobutaani