What is "isobutylene"

n. (context organic compound English) methylpropene; isobutene

n. used also in making gasoline components

Isobutylene (or 2-methylpropene) is a hydrocarbon of industrial significance. It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. At standard temperature and pressure it is a colorless flammable gas.