Iron-Catalyzed Chain Growth of Ethylene: In Situ Regeneration of ZnEt₂ by Tandem Catalysis

A dual catalyst system to implement in situ regeneration of ZnEt₂, the Chain Transfer Agent (CTA) in Catalyzed Chain Growth of ethylene (CCG), has been demonstrated. As in typical CCG systems, an Fe homogeneous catalyst is used to grow oligomeric chains that transfer rapidly to ZnEt₂. However, rather than liberating alkane products and destroying the expensive chain transfer agent via acid hydrolysis workup, a second Fe-alkyl catalyst, (BiPy)₂FeEt₂, has been introduced to regenerate ZnEt₂ via ethyl/alkyl exchange and liberate the oligomer chains as α-olefins via ß-hydride elimination. This improvement reduces the ZnEt₂ loading and leaves the chain growth catalyst competent, in contrast to Ni­(acac)₂ shown to be unsuitable for in situ tandem catalysis. These findings greatly enhance the industrial viability of the chemistry.