Well-defined vanadium complexes as the catalysts for olefin polymerization

Wu, Ji-Qian; Li, Yuesheng

doi:10.1016/j.ccr.2011.01.048

Cited by 115 publications

(94 citation statements)

References 104 publications

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“…Polymerization experiments were conducted in hexane using 0.5 lmol of the vanadium complex. The reaction temperature was set up at 30°C since the vanadium compounds are known to readily undergo reduction to lower oxidation states which are inactive in polymerization [22,23]. To overcome this problem, the reactivating agents are often used, even at low temperatures [23].…”

Section: Ethylene Homo-and Copolymerizationmentioning

confidence: 99%

“…The design and synthesis of new vanadium complexes which bear other chelating ligands attract however more and more interest recently [22][23][24][25][26][27][28][29][30]. It results from the interesting catalytic properties of this type of catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…Classical vanadium catalysts are able to produce high molecular weight polymers with narrow molecular weight distributions, high molecular weight amorphous ethylene/propylene copolymers, syndiotactic propylene [22,31,32]. The problem of using vanadium catalysts is their rapid deactivation associated with reduction of catalytically active vanadium species to inactive vanadium(II) species, especially at higher temperatures [22,23,31,32]. Adding chelating ligands to the vanadium compound can help in stabilizing the vanadium species at a high oxidation state [31].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

Białek

Fryga

Spaleniak

et al. 2017

Reac Kinet Mech Cat

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Novel vanadium complexes bearing [OSSO]-type ligands having two phenolato units linked through the -CH 2 S(CH 2 ) 4 SCH 2 -(1V) or -CH 2 S(CH 2 ) 2-SCH 2 -(2V) bridge are synthesized with good yields by reacting a deprotonated ligand with VCl 4 . They are then used in ethylene (co)polymerization after activation with EtAlCl 2 and Et 2 AlCl. In the presence of EtAlCl 2 , both complexes promote ethylene polymerization with very high activities, over 4 9 10 7 g/(mol h), leading to PEs with high molecular weight and narrow molecular weight distribution. The prepared complexes exhibit lower activity for ethylene/1-octene copolymerization. It is also revealed that the catalyst based on the -CH 2 S(CH 2 ) 4 SCH 2 -bridged complex shows both higher activity and higher comonomer incorporation ability than the catalyst based on the -CH 2 S(CH 2 ) 2 SCH 2 -bridged complex. Upon activation with Al(iBu) 3 /Ph 3 CB(C 6 F 5 ) 4 , complex 2V produces stereo-and regioirregular poly(1-octene), while 1V gives the isotactically enriched product.

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Section: Ethylene Homo-and Copolymerizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

Białek

Fryga

Spaleniak

et al. 2017

Reac Kinet Mech Cat

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“…The literature reflects the continued interest in catalysts for homo-and copolymerization of ethylene. Recently, after intensive exploration of metallocene and nonmetallocene group 4 complexes in these processes, the considerable attention is attracted by the catalysts of group 5 elements [1][2][3][4][5]. The vanadium complexes make an attractive goal for formulators in view of the fact that the classical vanadium catalysts display the unique characteristic as compared to the titanium-based ones.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2014

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Oxovanadium(IV) complexes with [ONNO]-type tetradentate Schiff base ligands: salen, acacen, aceten, acetph (H 2 salen = N,N′-ethylenebis(salicylideneimine), H 2 aceten = N,N′-ethylenebis(2-hydroxyacetophenoneimine), H 2 acacen = N,N′-ethylenebis(acetylacetonimine), H 2 a c e t p h = N , N ′ -p h e n y l e n e -1 , 2 -b i s (2-hydroxyacetophenoneimine)), were the first time investigated in ethylene polymerization and ethylene/1-octene copolymerization processes. In general, all these complexes are moderately active precatalyst for ethylene polymerization upon activation with EtAlCl 2 and they give high molecular weight linear polyethylenes. Their activity in copolymerization was found relatively low. However, they yielded copolymers with high 1-octene incorporation even at low comonomer concentrations in the feed. The catalytic performance in homo-and copolymerization was influenced by both the ligand structure and polymerization parameters (Al/ V molar ratio, polymerization temperature, comonomer feed concentration). In addition, the [VO(acacen)] was supported onto magnesium supports, and in the presence of various cocatalyst and at different reaction conditions it was screened as the catalyst of choice for ethylene homo-and copolymerization.

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“…et al reported that either VOCl3/Et3Al2Cl3 or VO(OtBu)3/Et3Al2Cl3 showed high cyclic dienes incorporation ability in the terpolymerization with ethylene and propylene [23]. Since the vanadium catalysts might be deactivated during the polymerization because of the reduction to low-valent, inactive species [27], introduction of bulky and polydentate ancillary ligands to stabilize active vanadium(V) species has been proven to be an effective approach to keep vanadium at high-oxidation and subsequently prolong the catalytic lifetime [28][29][30][31][32][33][34][35][36]. In our previous work, the synthesized [ONNO]-type and [ONN]-type oxovanadium(V) complexes also showed high catalytic activities and promising stabilities in copolymerization of ethylene with norbornene (NBE), and produced E/NBE copolymers with high NBE contents [37,38].…”

Section: Introductionmentioning

confidence: 99%

Facile, Efficient Copolymerization of Ethylene with Norbornene-Containing Dienes Promoted by Single Site Non-Metallocene Oxovanadium(V) Catalytic System

Wang

et al. 2017

Polymers

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Non-metallocene oxovanadium(V) complexes bearing either [ONNO]-type amine pyridine bis(phenolate) ligands or [ONN]-type amine pyridine phenolate ligands were employed as efficient catalysts to copolymerize ethylene with several unsymmetrical norbornene-containing dienes, such as 5-vinyl-2-norbornene (VNB), 5-ethylidene-2-norbornene (ENB) or dicyclopentadiene (DCPD), producing copolymers with high comonomer incorporations (VNB: 33.0 mol %; ENB: 30.4 mol %; DCPD: 31.6 mol %, respectively) and high molecular weight (VNB: 86.4 kDa; ENB: 256 kDa; DCPD: 86.4 kDa, respectively). The enchainment of the dienes was proven to be exclusive of vinyl-addition via the C=C double bond of the norbornene ring while the other double bond was retained near the backbone without crosslinking. During the copolymerization of ethylene with ENB, a positive 'comonomer effect' was observed. The catalytic activities of the catalysts as well as the molecular weights and comonomer incorporations of the resultant copolymers could be tuned within a wide range by varying the structures of the catalysts and copolymerization conditions. The [ONN]-type oxovanadium(V) complexes showed higher catalytic activities than those of [ONNO]-type oxovanadium(V) complexes, irrespective of the structure of the dienes. In addition, the dominant chain transfer pathway of the non-metallocene oxovanadium(V) catalytic system promoted copolymerization was proven to be transfer to aluminum compounds.

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Well-defined vanadium complexes as the catalysts for olefin polymerization

Cited by 115 publications

References 104 publications

Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

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

Facile, Efficient Copolymerization of Ethylene with Norbornene-Containing Dienes Promoted by Single Site Non-Metallocene Oxovanadium(V) Catalytic System

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