isobuteen

Isobutene, also known as isobutylene or 2-methylpropene, is a branched alkene with the chemical formula C4H8. It is a colorless, flammable gas at room temperature and pressure. Isobutene is one of the four structural isomers of butene, the others being 1-butene, cis-2-butene, and trans-2-butene. It has a characteristic gasoline-like odor.

Industrially, isobutene is primarily produced as a byproduct of petroleum refining, specifically from fluid catalytic cracking and steam cracking processes. It can also be produced through the dehydration of tert-butyl alcohol or by the dehydrogenation of isobutane.

Isobutene is a versatile chemical intermediate. Its most significant use is in the production of methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), which are octane enhancers for gasoline. However, the use of MTBE has declined in some regions due to environmental concerns. Isobutene is also a key component in the synthesis of polyisobutylene, a polymer used in lubricants, adhesives, and sealants. Furthermore, it is used to produce tert-butyl alcohol, antioxidants, and other specialty chemicals. It is also employed in the production of butyl rubber, a synthetic rubber known for its low gas permeability, used in inner tubes and seals.