But-2-ene
It is a petrochemical, produced by the catalytic cracking of crude oil or the dimerization of ethylene.Its main uses are in the production of high-octane gasoline (petrol) on alkylation units and butadiene,[4] although some but-2-ene is also used to produce the solvent butanone via hydration reaction to butan-2-ol followed by oxidation.The two isomers are extremely difficult to separate by distillation because of the proximity of their boiling points (~4 °C for cis and ~1 °C for trans[5]).However, separation is unnecessary in most industrial settings, as both isomers behave similarly in most of the desired reactions.Butane and but-1-ene are common impurities, present at 1% or more in industrial mixtures, which also contain smaller amounts of isobutene, butadiene and butyne.