2methylpropene

2-methylpropene, commonly known as isobutene or isobutylene, is an organic compound with the formula C4H8. It is the simplest branched alkene, with the structure CH2=C(CH3)2. Isobutene is a colorless, volatile gas at room temperature and is highly flammable. In industry it is usually stabilized with small amounts of polymerization inhibitors to prevent premature polymerization during handling and storage.

Production and occurrence: In refinery and petrochemical operations, isobutene is produced as a byproduct or coproduct. The principal industrial route is the dehydrogenation of isobutane (C4H10 → C4H8 + H2) over suitable catalysts. It can also be formed by dehydration of tert-butanol. Purified isobutene is typically collected as a gas and stored under appropriate inhibitors and low temperatures.

Uses: The dominant use of isobutene is as a monomer for the production of polyisobutylene (PIB), a low-density polymer used in lubricants, adhesives, and sealants. It is also employed to prepare tert-butyl derivatives, most notably methyl tert-butyl ether (MTBE) by reaction with methanol in acid-catalyzed processes. Additionally, it serves as a reactive diluent or comonomer in various polymerization and alkylation applications.

Reactions and properties: Isobutene undergoes typical alkene additions (hydrohalogenation, hydration, etc.) and readily polymerizes under radical conditions. It is readily ignitable and forms explosive mixtures with air. Handling requires containment, proper ventilation, and storage with stabilizers to prevent polymerization.