Isobutane, also known as isobutane, 2-methylpropane or methylpropane, is a chemical compound with the molecular formula HC(CH3)3. It is an isomer of butane. Isobutane is a colorless, odorless gas. It is the simplest alkane with tertiary carbon atoms. Isobutane is used as a precursor molecule in the petrochemical industry, for example in the synthesis of isooctane. [6

Isobutane is obtained by isomerizing butane.

Isobutane is the main feedstock for the alkylation unit of a refinery. Using isobutane, a highly branched gasoline-grade "blendstock" is produced for good combustion characteristics. Typical products produced from isobutane are 2,4-dimethylpentane and especially 2,2,4-trimethylpentane. [7]

Isobutane is used as a diluent in the Chevron Phillips slurry process used to make HDPE. When the slurry polyethylene is removed, the isobutane is "flashed", then condensed and recycled back to the loop reactor for this purpose.

Isobutane is oxidized to tert-butyl hydroperoxide, which is subsequently reacted with propylene to form propylene oxide. tert-butanol produced as a by-product is often used to make gasoline additives such as methyl tert-butyl ether

Isobutane is used as a refrigerant. [10] Use in refrigerators began in 1993, when Greenpeace, together with the former East German company Foron [de], proposed the Greenfreeze project. [11][12] In this regard, mixtures of pure, dry "isobutane" (R-600a) (i.e., isobutane mixtures) have negligible ozone depletion potential and very low global warming potential (3.3 times the GWP of carbon dioxide) and can be used in conventional stationary refrigeration and air conditioning systems as R-12, R-22 (both known under the trademark Freon), R-134a and other chlorofluorocarbons A functional alternative to hydrocarbon or hydrofluorocarbon refrigerants.