Isobutane

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Categories: Alkanes | Refrigerants | Propellants

Isobutane
Image:Isobutane1.png	Image:Isobutane2.png
Image:Isobutane3.png
IUPAC name	Isobutane Methylpropane
Other names	2-Methylpropane
Identifiers
CAS number	[75-28-5]
SMILES	C(C)CC
Properties
Molecular formula	C₄H₁₀
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	-159.6 °C, 114 K, -255 °F
Boiling point	-11.7 °C, 261 K, 11 °F
Solubility in water	Insoluble
Hazards
MSDS	External MSDS
MSDS	External MSDS
EU classification	Highly flammable (F+)
NFPA 704	4 1 0
R-phrases	R12
S-phrases	(S2), S9, S16
Flash point	flammable gas
Autoignition temperature	460 °C
Explosive limits	1.8–8.4%
Related compounds
Related alkane	Butane
Related compounds	Isopentane Neopentane
Supplementary data page
Structure and properties	n, ε_r, etc.
Thermodynamic data	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]
Its UN number (for hazardous substances see shipping) is UN 1969.

Nomenclature

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.