butan

Butan is the saturated hydrocarbon with the formula C4H10. In common usage, butan refers to butane, which exists in two structural isomers: n-butane, a straight-chain form, and isobutane, also called methylpropane, a branched form. Both are part of the alkane family and share similar chemical properties.

Physically, both isomers are colorless and flammable gases at room temperature that can be compressed into liquids. Their boiling points are approximately −0.5 °C for n-butane and −11.7 °C for isobutane. Butane is relatively nonpolar and has low reactivity, making it useful as a fuel and solvent in some applications.

Occurrence and production occur mainly in natural gas processing and petroleum refining. Butane is present in small amounts in natural gas and is separated during gas processing and crude oil distillation. In commerce it is often supplied as liquefied petroleum gas (LPG) when stored under pressure in cylinders or tanks, or used as a component of LPG blends.

Uses are diverse. The primary applications are as a fuel for heating, cooking, and portable stoves; as a propellant in aerosols; and as a feedstock in petrochemical processes to produce light olefins and other chemicals. Isobutane is also a common component of LPG blends that are distributed for household or industrial use. The compound is sometimes used as a solvent in specialized industrial contexts, though this is less common today.

Safety and handling require attention to flammability. Butane should be stored in approved containers away from heat and ignition sources, with leaks addressed promptly. Adequate ventilation is important to avoid accumulation, and inhalation of concentrated vapors can be hazardous.