Industrial Chemical Isobutylene Colourless Gaseous

Isobutylene (also called 2-methylpropene, isobutene, and γ-butylene because chemists aren’t wonderful at sticking to a one naming system) is a colourless, gaseous hydrocarbon at room temperature.

Its flash point is -80 ˚C meaning that above this temperature, if an ignition source is present, isobutylene will ignite. Since the coldest temperature ever recorded on Earth was -89 ˚C, isobutylene is only a spark away from flames nearly everywhere on earth at all times.

Isobutylene is widely used in the synthesis of many things, largely because it contains a double bond which can be easily reacted to form other products. It can, for example, react with ethanol to form ethyl tert-butyl ether (ETBE), a gasoline additive that raises the octane number, making the fuel more resistant to knocking, or spontaneous combustion. Or it can be combined with itself in a long chain to form a polymer, butyl rubber.

Polymer and Chemical Grade Isobutylene is typically obtained by dehydrating tertiary butyl alcohol (TBA) or catalytic dehydrogenation of isobutane (Catofin or similar processes). Gasoline additives methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), respectively, are produced by reacting methanol or ethanol with isobutylene contained in butene streams from olefin steam crackers or refineries, or with isobutylene from dehydrated TBA. Isobutylene is not isolated from the olefin or refinery butene stream before the reaction as separating the ethers from the remaining butenes is simpler. Isobutylene can also be produced in high purities by "back-cracking" MTBE or ETBE at high temperatures and then separating the isobutylene by distillation from methanol or

Isobutylene is a byproduct in the ethenolysis of diisobutylene to prepare neohexene:

(CH3)3C-CH=C(CH3)2 + CH2=CH2 → (CH3)3C-CH=CH2 + (CH3)2C=CH2