Diisobutene
Diisobutene refers to a pair of organic compounds with the overall formula C8H16. The isomers have the same carbon skeleton but differ in the location of the C=C bond. Both are colorless liquids with very similar physical properties. These compounds arise via the acid catalyzed dimerization of isobutene, a reaction that proceeds via the carbocation. The process also leads to some triisobutenes and tetraisobutenes. The commercial material is typically a mixture of isomers, with the terminal 1-ene being the major component. The preferential formation of the less substituted alkene can be counterintuitive to chemists, but can be explained by assessing its transition state.