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.[1]
| align="center" colspan="5" | Diisobutene isomers | ||
|---|---|---|---|
| Structure | CH2=C(CH3)-CH2C(CH3)3 | (CH3)2C=CHC(CH3)3 | |
| Systematic name | 2,4,4-Trimethyl-1-pentene | 2,4,4-Trimethyl-2-pentene | |
| CAS number | [107-39-1] | [107-40-4] | |
| Density | 0.7150 g/mL | 0.7218 g/mL | |
| Melting point | -93.5 °C | -106.3 °C | |
| Boiling point | 101.4 °C | 104.9 °C |
These compounds are used as precursors to isononylol and octylphenols by hydroformylation/hydrogenation and phenol alkylation, respectively. Both are precursors to plasticizers.[2] The isononylol is a precursor to 3,5,5-trimethylhexyl acetate, a commercial fragrance.[3] Diisobutenes were once of interest as components for automotive fuels.