Catalyst Deactivation Processes During 1-Hexene Polymerization

The catalyst [Cp₂Zr(μ-Me)₂AlMe₂]⁺[B(C₆F₅)₄]⁻ (1) has been studied by electrospray ionisation mass spectrometry (ESI-MS) in order to better understand the complexities of catalyst deactivation in the polymerisation of 1-hexene. Using offline, online and flow-based methods, we observe that zirconium π-allyl species are unstable in solution and previously unobserved dimethylalane complexes are more stable. The dimethylalane complexes are resistant to further 1-hexene additions and their formation represent a new pathway for catalyst deactivation.