text: The insertion of ethylene and propylene into titanium alkyls is the cornerstone of Ziegler-Natta catalysis, the commercial route of polyethylene and polypropylene.  This technology mainly involves heterogeneous catalysts, but it is widely assumed that the principles and observations on homogeneous systems are applicable to the solid-state versions.  Related technologies include the Shell Higher Olefin Process which produces detergent precursors. the olefin can be coordinated to the metal before insertion. Depending on the ligand density of the metal, ligand dissociation may be necessary to provide a coordination site for the olefin.