Tripropylene, also known as propylene trimer, is usually sold as a mixture of structural isomers of nonene.

[2] This mixture is obtained by oligomerization of propene: In this process, two double bonds are lost and one is retained as illustrated by the isomer shown in the figure.

[4] The reaction proceeds via the formation of a carbocation ((CH3)2CH+), which attacks another propylene unit, generating a new carbocation, etc.

This kind of process affords mixtures (C3H6)n. Like other alkenes, propylene trimer is used as an alkylating agent.

A number of surfactants and lubricants are produced by alkylation of aromatic substrates.