Ethylene polymerizations, and the copolymerizations of ethylene with hexene or norbornene with highly active mono(β‐enaminoketonato) vanadium(III) catalysts

Abstract

Five novel vanadium(III) complexes [PhN = C(R2)CHC(R1)O]VCl2(THF)2 (4a: R1 = Ph, R2 = CF3; 4b: R1 = t‐Bu, R2 = CF3; 4c: R1 = CF3, R2 = CH3; 4d: R1 = Ph, R2 = CH3; 4e: R1 = Ph, R2 = H) have been synthesized and characterized. On activation with Et2AlCl, all the complexes, in the presence of ethyl trichloroacetate (ETA) as a promoter, are highly active precatalysts for ethylene polymerization, and produce high molecular weight and linear polymers. Catalyst activities more than 16.8 kg PE/mmolV h bar and weight‐average molecular weights higher than 173 kg/mol were observed under mild conditions. The copolymerizations of ethylene and norbornene or 1‐hexene with the precatalysts were also explored, which leads to high molecular weight copolymers with high comonomer incorporation. Catalyst activity, comonomer incorporation, and polymer molecular weight as well as polydispersity index can be controlled over a wide range by the variation of precatalyst structure and the reaction parameters such as Al/V molar ratio, comonomer feed concentration, and polymerization temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2038–2048, 2008

Oxovanadium(IV) complexes with [ONNO]-chelating ligands as catalysts for ethylene homo- and copolymerization

“…The microstructures of two selected poly(ethylene-co-1-octene)s synthesized with [VO(salen)] and [VO(aceten)] were analyzed using 13 C NMR. The spectra of both copolymers were similar to each other, hence only the spectrum of the sample produced by [VO(salen)]/EtAlCl 2 is presented in Fig.…”

“…A good thermal stability can also be expected from single-site catalysts which are based on bis(imino)pyrrolyl v a n a d i u m ( I I I ) c o m p l e x e s [ 1 2 ] . M o n o (β-enaminoketonato)vanadium(III) complexes show high catalytic activities in ethylene polymerization and an excellent capacity to copolymerize ethylene and 1-olefins or cycloolefins [13], while vanadium(III) complexes with iminopyrrolide ligands [14] or tridentate phenoxy-phosphine ligands [15] exhibit high activity in ethylene polymerization even at 70°C, and they can also efficiently catalyze the copolymerization process of ethylene with 10-undecen-1-ol to produce copolymers with around 15 mol % of comonomer. (Arylimido)(aryloxo)vanadium(V) complexes show high activity in ethylene polymerization and a good potential to incorporate the norbornene monomer [16].…”

“…The information is also vital that the majority of vanadium complexes shows a better activity in combination with simple alkylaluminium compounds, especially EtAlCl 2 and Et 2 AlCl [10,[12][13][14][15][16][17][18]21], which makes them good alternatives for MAO activated zirconium and titanium-based catalysts.…”

Ethylene/1-olefin copolymerization behaviour of vanadium and titanium complexes bearing salen-type ligand

“…The classical vanadium catalysts are known for their ability to produce high molecular weight polyethylene, syndiotactic propylene, and ethylene/1-olefin copolymers with the high 1-olefin content; they are able to perform random and super-random copolymerization [8,14,15]. Their specific catalytic properties made them applicable in the production of poly(ethylene-co-propylene) and poly(ethyleneco-propylene-co-diene) elastomers [8,14,15].…”

“…Their specific catalytic properties made them applicable in the production of poly(ethylene-co-propylene) and poly(ethyleneco-propylene-co-diene) elastomers [8,14,15]. Hence, much interest was attracted by postmetallocene complexes which had vanadium as the central metal, both for homoand copolymerization of olefins [5][6][7][15][16][17][18][19][20][21]. Nomura and Wang [7] used (arylimino)(aryloxo)vanadium(V) complexes in ethylene/1-hexene copolymerization.…”