isoprene or
2-methyl-1,3-butadiene (ī`səprēn, by
'tədī`ēn), colorless liquid organic compound. It is a hydrocarbon, and is insoluble in water but soluble in many organic solvents; it boils at 34°C;. The isoprene molecule contains two double bonds. It is readily polymerized by the use of special catalysts; large numbers of isoprene molecules join together to form a single large, threadlike polyisoprene molecule. Isoprene polymers also occur naturally. The natural rubber caoutchouc is
cis-1,4-polyisoprene, and
trans-1,4-polyisoprene is present in the natural rubbers balata and gutta-percha. (The
cis and
trans polyisoprenes are structural isomers.)