Isobutene

Isobutene, also known as isobutylene, is an organic compound with the formula C4H8. It is a colorless, flammable gas at room temperature and a terminal alkene with the structure CH2=C(CH3)2.

IUPAC name: 2-methylpropene. It is produced industrially mainly by the dehydrogenation of isobutane to isobutene and hydrogen in refinery processes, with dehydration of tert-butyl alcohol as a secondary route. It can also form as a byproduct in various hydrocarbon processing streams.

Reactivity and properties: Isobutene readily undergoes electrophilic addition across its carbon–carbon double bond. Hydration of isobutene yields tert-butyl alcohol (2-methyl-2-propanol). Addition of hydrogen halides or halogens affords corresponding alkyl halides. It polymerizes readily to polyisobutylene, a polymer used as a lubricant base stock and as a viscosity modifier in fuels and lubricants.

Applications: The major uses of isobutene include production of polyisobutylene and synthesis of gasoline additives. It is a key intermediate for the manufacture of methyl tert-butyl ether (MTBE) through reaction with methanol, historically used as a gasoline oxygenate. It also serves as a building block for various alkylated and functionalized hydrocarbons.

Safety and handling: Isobutene is a flammable gas. It is stored and handled under appropriate controls to avoid ignition sources and is typically managed in pressurized containers or process units with proper ventilation. Like many reactive alkenes, it can form hazardous byproducts under improper storage conditions and should be handled with standard industrial precautions.