What does isobutane mean?
Isobutane is the common name for 2-methylpropane, a colorless and flammable hydrocarbon gas with the formula C₄H₁₀. Unlike normal butane, whose four carbon atoms form a straight chain, isobutane has a branched carbon structure. This distinction matters in chemistry and industrial applications because the two compounds can have different physical and combustion properties. Isobutane is especially useful as a refrigerant, including in refrigerators and air-conditioning systems, and it also serves as a fuel and an aerosol propellant. Although it is a gas at ordinary room temperature and pressure, it can be liquefied under pressure for storage and transport. Its name combines the chemical prefix “iso-” with “butane,” making its relationship to the straight-chain hydrocarbon explicit.
nounIsobutane is a colorless, flammable gaseous alkane with the formula C₄H₁₀. It is the branched-chain isomer of butane and is used chiefly as a refrigerant, fuel, and aerosol propellant.
- A colorless, flammable gaseous alkane, C₄H₁₀, used as a refrigerant, fuel, and propellant.
"Isobutane is widely used as a refrigerant in refrigerators and air-conditioning systems."
"The technician checked the isobutane charge in the cooling system."
"Isobutane is added to aerosol products to help propel their contents."
Usually used as an uncountable chemical name; the plural is uncommon and refers to multiple quantities or units.
"The facility stores isobutanes in pressurized cylinders."
Isobutane and butane share the same molecular formula, yet behave differently because their carbon chains take different shapes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does isobutane come from?
The name isobutane combines the chemical prefix “iso-” with butane to identify the branched isomer of the four-carbon alkane. The prefix “iso-” is used in chemical nomenclature to indicate a branched arrangement of atoms. The name therefore distinguishes isobutane, or 2-methylpropane, from normal butane.
How isobutane is actually used
In technical and commercial contexts, isobutane is usually treated as an uncountable chemical name. It should not be confused with butane, its straight-chain isomer.
Easily confused with isobutane
Butane is the straight-chain isomer of isobutane; both have the formula C₄H₁₀, but their molecular structures differ.