Alternative aluminum-based cocatalysts for the iron-catalyzed oligomerization of ethylene

Abstract

Multinuclear aluminum cocatalysts have been obtained by the reaction of various phenols, alcohols or diols with trimethylaluminum and were used in situ or as isolated, well-defined species, for the activation of an iron(ii) or an iron(iii) pre-catalyst for the oligomerization of ethylene. The best cocatalyst candidate involves 2,2'-biphenol () in a /AlMe3 ratio of 2/3.

Recent advances in Ni-mediated ethylene chain growth: Nimine-donor ligand effects on catalytic activity, thermal stability and oligo-/polymer structure

“…By contrast, pyridinylimine-based N^N-nickel pre-catalysts, in the main, promote the conversion of ethylene to α-olefins with the ligand structure, substitution effects and process conditions playing an important role on the catalytic activity and product distribution [24,25,29]. Elsewhere, Braunstein and co-workers have made significant contributions in the field of catalytic ethylene oligomerization [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] and, in particular, with regard to the preparation and application of P^N [30][31][32]34,36], P^P [38,40], N^P^N [37] and SHOP-type [35,38] nickel complexes for olefin oligomerization. In general, however, it still remains difficult to achieve performance characteristics that can compete with industrial catalysts.…”

Insight into Oxide‐Bridged Heterobimetallic Al/Zr Olefin Polymerization Catalysts

“…Attempts to isolate the [ i Bu 5 Al 2 O ⋅ THF] − species were unsuccessful and probably frustrated by the formation of a variety of larger i Bu‐alumoxane (TIBAO) species, but [(TBBP)Al i Bu], the side product of the last step shown in Scheme , could be isolated in its dimeric form (see above). Although biphenolate alkylaluminums were recently found to be active cocatalysts in ethene oligomerization, our previous findings indicate that the dimer [(TBBP)Al i Bu] 2 itself should not be an activator.…”

Paradox of Late Transition-Metal Catalysts in Ethylene Polymerization

“…Notably, the formation of hyperbranched polyethylenes by nickel catalysts displaying properties characteristic of thermoplastic elastomers shows great promise for these materials to be employed as alternatives to elastomeric ethylene copolymers. [25][26][27] With regard to the preparation and application of nickel catalysts, a large number of studies have started from the modification of α-diimine ligand to form an extension of the bidentate N^N system to P^N, [28][29][30][31] P^P, [32][33] N^P^N [34] and SHOP-types [35] and other tridentate coordination systems. They will be introduced separately in the following.…”