Isobutane

Isobutane (i-butane), also known as methylpropane, is a chemical compound with molecular formula C
4H
10 and is an isomer of butane. It is the simplest alkane with a tertiary carbon. 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. Some portable camp stoves use a mixture of isobutane with propane, usually 80:20. Isobutane is used as a feedstock in the petrochemical industry, for example in the synthesis of isooctane.

Nomenclature

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. Since the longest continuous chain in isobutane contains only three carbon atoms, the full systematic name is 2-methylpropane but the locant (2-) is typically omitted as redundant; C2 is the only position on a propane chain where a methyl substituent can be located without altering the main chain and forming the constitutional isomer n-butane.

Isobutane (data page)

This page provides supplementary chemical data on isobutane.

Material Safety Data Sheet

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source such as SIRI, and follow its directions.

Structure and properties

Thermodynamic properties

Vapor pressure of liquid

Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.

Spectral data

References

Except where noted otherwise, data relate to standard ambient temperature and pressure.

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