Heterogeneous catalysts produce the vast majority of polyolefin materials.1 The workflow to generate an active heterogeneous catalyst for olefin polymerization usually involves activation of a Group 4 metal pre-catalyst with a large excess of alkylaluminum2 or partially hydrolyzed alkylaluminumin3 in the presence of a high surface area oxide. Late transition metal Ni-or Pd-catalysts for olefin polymerization incorporate monomers containing heteroatoms, but are generally incompatible with this heterogeneous workflow. We found the silylium-like surface species [iPr3Si][(RFO)3Al–OSi≡)] activates (N^N)Pd(CH3)Cl (N^N = Ar-N=CMeMeC=N-Ar, Ar = 2,6-bis(diphenylmethyl)-4-methylbenzene) by chloride ion abstraction to form [(N^N)Pd–CH3][(RFO)3Al–OSi≡)], which provide a new method to form active species for olefin polymerization. A combination of FTIR, solid-state NMR spectroscopy, and reactions with CO or vinyl chloride establish that the supported catalyst shows similar reactivity patterns as its homogeneous counterpart. Supported (N^N)Pd–CH3+ catalyzes the polymerization of ethylene with similar activities as [(N^N)Pd–CH3]+ in solution and incorporates up to 0.4 % methyl acrylate in copolymerization reactions. It produces polymers with significantly higher molecular weight than the solution catalyst and generates the highest molecular weight polymers currently reported in copolymerization reactions of ethylene and methyl acrylate.

Supported palladium catalyst for the polymerization of olefins prepared by halide abstraction using surface R3Si+ species

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.