The company also produces other chemical products such as benzene, butadiene, toluene, xylene and isoprene. Synthetic rubbers are often based on butadiene, which is structurally related to isoprene. Polyisoprene is a collective name for polymers that are produced by polymerization of isoprene. These compounds consist of methanol, isoprene, acetone, ethanol and other alcohols. Butyl rubber is made by cationic polymerisation of isobutylene with about 2 - 7% isoprene. One important reaction that uses these activated isoprene donors is steroid biosynthesis. Dolichol is a lipid molecule composed of repeating isoprene units. He also published three papers describing the polymerisation of isoprene to prepare synthetic rubber. It is a polymer of isoprene which forms a rubber-like elastomer. It belongs to the abietane diterpene group of organic compounds derived from four isoprene units. Farnesol is produced from 5-carbon isoprene compounds in both plants and animals. Farnesol is produced from isoprene compounds in both plants and animals. Lycopene is a symmetrical tetraterpene assembled from eight isoprene units. Terpenoids, produced by conifers and angiosperms, consist of ring structures formed of isoprene (CH) units. Lipids are divided into eight categories based on ketoacyl and isoprene.