Nickel catalyzed displacement reaction

A process for displacing alkyl groups from a first trialkyl aluminum or mixture thereof, said process comprising contacting said first trialkyl aluminum or mixture thereof with an .alpha.-olefin or mixture thereof containing a different distribution of carbon atoms than the alkyl groups in said first trialkyl aluminum or mixture thereof, in the presence of a nickel catalyst at a temperature of about -10.degree. to 150.degree. C. whereby said .alpha.-olefins displace at least part of the alkyl groups in said first trialkyl aluminum or mixture thereof to form a second trialkyl aluminum or mixture thereof, further characterized by adding a deactivating amount of a catalyst poison selected from lead and compounds thereof which are capable of deactivating said nickel catalyst after the displacement reaction has proceeded to the desired extent but before any significant isomerization of the .alpha.-olefins to internal olefins has occurred.