Methylpropane

Methylpropane, more commonly known as isobutane, is an alkane with the chemical formula C4H10. Its IUPAC name is 2-methylpropane, and methylpropane is a historical or less common name. The molecule is branched, with a central carbon bonded to three methyl groups and one hydrogen, giving the structural formula CH3-CH(CH3)-CH3 (often written as (CH3)3CH).

Isobutane is a colorless gas at room temperature that can be liquefied under modest pressure. Its boiling point is well below ambient temperature, and it is highly flammable. In industry, it is typically stored as a compressed gas or a liquefied gas mixture.

Production and occurrence occur during petroleum refining and natural gas processing. It is commonly recovered from LPG streams and other hydrocarbon-processing fractions. As a feedstock, isobutane can be dehydrogenated to form isobutene (2-methylpropene), which is used to produce a variety of petrochemical products, including alkylation feedstocks and other derivatives. It is also widely utilized directly in consumer products.

Applications include use as a fuel in portable stoves and lighters, a propellant in aerosol products, and a refrigerant under the designation R-600a in domestic refrigerators and some air conditioning systems. Its relatively low environmental impact among hydrofluorocarbons has contributed to its adoption as an alternative to heavier, higher-GWP refrigerants in suitable equipment.

Safety considerations center on its flammability and tendency to form pressure-containing mixtures with air. Leaks should be avoided, and installations should be well ventilated and designed to prevent accumulation in enclosed or low-lying spaces.