Nonene
Nonene is an alkene with the molecular formula C9H18. Many structural isomers are possible, depending on the location of the C=C double bond and the branching of the other parts of the molecule. Industrially, the most important nonenes are trimers of propene. This mixture of branched nonenes is used in the alkylation of phenol to produce nonylphenol, a precursor to detergents, which are also controversial pollutants.