The most important industrial application is the nickel-catalyzed synthesis of adiponitrile () synthesis from buta-1,3-diene (). Adiponitrile is a precursor to hexamethylenediamine (), which is used for the production of certain kinds of Nylon. The DuPont ADN process to give adiponitrile is shown below:
This process consists of three steps: hydrocyanation of butadiene to a mixture of 2-methyl-butene-3-nitrile (2M3BM) and pentene-3-nitrile (3PN), an isomerization step from 2M3BM (not desired) to 3PN and a second hydrocyanation (aided by a Lewis acid cocatalyst such as aluminium trichloride or triphenylboron) to adiponitrile.