Significant Polar Comonomer Enchainment in Zirconium‐Catalyzed, Masking Reagent‐Free, Ethylene Copolymerizations

Abstract

In principal, the direct copolymerization of ethylene with polar comonomers should be the most efficient means to introduce functional groups into conventional polyolefins but remains af ormidable challenge.D espite the tremendous advances in group 4-centered catalysis for olefin polymerization, successful examples of ethylene + polar monomer copolymerization are rare,e specially without Lewis acidic masking reagents.Here we report that certain group 4catalysts are very effective for ethylene + CH 2 =CH(CH 2 ) n NR 2 copolymerizations with activities up to 3400 Kg copolymer mol À1 -Zr h -1 atm -1 ,and with comonomer enchainment up to 5.5 mol % in the absence of masking reagents.G roup 4c atalyst-aminoolefin structure-activity-selectivity relationships reflect the preference of olefin activation over free amine coordination, which is supported by mechanistic experiments and DFT analysis.These results illuminate poorly understood facets of d 0 metal-catalyzed polar olefin monomer copolymerization processes.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Recent Advances in Transition Metal‐Based Catalysts for Ethylene Copolymerization with Polar Comonomer

“…The fact that group 4‐based catalysts are extensively studied for olefin polymerization, the investigation of Lewis acidic masking agents‐free ethylene copolymerization with polar comonomer is rarely reported. Hence, Chen et al [31] . have evaluated group 4‐based efficient catalysts for ethylene copolymerization with polar amino olefin (CH 2 =CH(CH 2 ) n NR 2 ) (Figure 3).…”

Synthesis of high thermal stability Polypropylene copolymers with pyrrole functionality

“…at 140ºC. In addition, the accuracy of GPC for polar polyolefins has been called into question [22][23][24]. Consequently, 1 H NMR has been used to estimate the molar mass of the copolymers, assuming that the main termination mechanisms of chain growing are those producing a chain-end olefin [25,26].…”

Recent Advances in Coordination‐Insertion Copolymerization of Ethylene with Polar Functionalized Comonomers

“…disclosed a masking reagent‐free Zr catalyst system for copolymerization of ethylene with amino‐olefins (AO) (Scheme 1). [ 3 ] High activity and high comonomer enchainment could be achieved by fine‐tuning the structure of both the catalyst and comonomer, which led to selective olefin activation over terminal amine coordination. The effect of the linker length in AO has been studied, showing that the long‐chain AOs gave the best result in terms of activity and incorporation…”