Vinylic Polymerization and Copolymerization of Norbornene and Ethene by Homogeneous Chromium(III) Catalysts

Peucker, Uwe; Heitz, Walter

doi:10.1002/1521-3935(20010501)202:8<1289::aid-macp1289>3.0.co;2-e

Cited by 25 publications

(16 citation statements)

References 17 publications

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“…The binuclear chromium(III) complexes Cr-11 to Cr-14 of the general type [Cp CrMeCl] 2 [Cp = cyclopentadienyl, pentamethylcyclopentadienyl (Cp*), indenyl, fluorenyl] were synthesized to investigate both the electronic nature and the steric demand of substituted cyclopentadienyl ligands [107] on the polymerization activity of norbornene when activated with MAO [120]. The catalyst activity increased with the electron donating character of the Cp -ligands (up to 88% yield, calculated activity 1.8 × 10 4 g polymer /mol Cr h [121] for Cp = fluorenyl), whereas the steric demand affected the crystallinity of the obtained polynorbornenes.…”

Section: Chromium Catalystsmentioning

confidence: 99%

Metal catalysts for the vinyl/addition polymerization of norbornene

Blank

Janiak

2009

Coordination Chemistry Reviews

329

208

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Section: Chromium Catalystsmentioning

confidence: 99%

Metal catalysts for the vinyl/addition polymerization of norbornene

Blank

Janiak

2009

Coordination Chemistry Reviews

329

208

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“…[1][2][3][4] As for chromium as a transition metal, cyclopentadienyl complexes are well known for ethylene polymerization. [5][6][7][8][9][10][11][12] Recently, non-cyclopentadienyl chromium catalysts have been reported. [13][14][15][16][17][18][19][20][21][22] These homogeneous catalysts have moderate to high activity depending on the ligand structures.…”

Section: Introductionmentioning

confidence: 97%

Ethylene Polymerization with Silica-Supported Cr[N(SiMe3)2]3/Alumoxane Catalyst

Monoi¹,

Ikeda²,

Ohira³

et al. 2002

Polym J

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ABSTRACT:A new silica-supported non-cyclopentadienyl chromium catalyst having high activity for ethylene polymerization is presented. The catalyst was prepared by supporting tris[bis(trimethylsilyl)amido]chromium(III) Cr[N(SiMe 3 ) 2 ] 3 and alumoxane on silica. The best activity was attained by supporting Cr[N(SiMe 3 ) 2 ] 3 (0.2 wt%-Cr for silica) on silica calcined at 350• C and next supporting a modified-methylalumoxane (Al/Cr molar ratio = 20). Activity during the slurry-phase polymerization was 75100 g-PE/mmol-Cr·hr at 103• C and 1.4 MPa ethylene partial pressure in isobutane. The obtained polyethylene had a relatively high molecular weight and broad molecular weight distribution (HLMFR = 15.6 g/10 min, M w = 330000, M w /M n = 33.0). The calcination temperature of silica had significant influence on the catalyst performance. As calcination temperature increased, short branches, mainly n-butyl and some ethyl branches, were introduced into the resulting polyethylene. There has been increasing interest in the discovery and development of non-cyclopentadienyl transition metal catalysts using titanium, zirconium, iron, nickel, and palladium for ethylene polymerization. [1][2][3][4] As for chromium as a transition metal, cyclopentadienyl complexes are well known for ethylene polymerization. [5][6][7][8][9][10][11][12] Recently, non-cyclopentadienyl chromium catalysts have been reported. [13][14][15][16][17][18][19][20][21][22] These homogeneous catalysts have moderate to high activity depending on the ligand structures. We have been exploring noncyclopentadienyl chromium catalysts because different characteristics could be expected for chromium as a group 6 element from the group 4 elements like titanium and zirconium, the group 8 element like iron and group 10 elements like nickel and palladium. We present a new heterogeneous non-cyclopentadienyl chromium catalyst having high activity for ethylene polymerization with unique features by supporting the tris[bis(trimethylsilyl)amido]chromium(III) complex Cr[N(SiMe 3 ) 2 ] 3 as a transition metal component and alumoxane as an organometallic component on silica. The characteristics of this catalyst influence polymerization activity and polymer structure (molecular weight, molecular weight distribution, and chain branching). The polymerization mechanism is discussed.

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“…Increasing the amount of olefins 4a-d resulted in a decrease of molecular weights and reduction of yields of PN as also reported previously in related reports. [9][10][11][12][13] 1 H NMR spectroscopy of PN obtained using an excess of 4 proved that PN chains are terminated by the corresponding olefinic moiety. Most significant reductions of molecular weights and yields were observed with 4b.…”

Section: Model Reactionsmentioning

confidence: 99%

“…[4][5][6][7] In an extension of this work we have shown that norbornene polymerizations using the system [NiBr(NPMe 3 )] 4 /MAO are terminated upon addition of olefins [8] as also found previously for numerous transition metal complexes (including Ni). [9][10][11][12][13] Chain terminations of polynorbornenes by addition of olefins occur by addition of the olefin to the active chain end and subsequent b-H elimination. In consequence, one chain end of polynorbornene is functionalized by the corresponding olefin moiety.…”

Section: Introductionmentioning

confidence: 99%

Grafting of Vinyl‐Type Polynorbornene on Polybutadiene and Polyisoprene

Schroers

Demeter²,

Dehnicke

et al. 2002

Macro Chemistry & Physics

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High molecular weight vinyl‐type polynorbornene was obtained by polymerization of norbornene initiated by [NiBr(NPMe3)]4/B(C6F5)3. Polymerization in the presence of olefins resulted in termination of polynorbornene chains by olefinic moieties. Molecular weights of polynorbornenes terminated by vinylidene compounds are lower than those terminated by vinyl and vinylene compounds. Corresponding polymerizations with polybutadiene and polyisoprene yielded graft copolymers with polynorbornene as grafts without contamination by homopolymerized polynorbornene. Grafting reactions were proved by spectroscopy, GPC, and degradation experiments using OsO4. GPC traces (refractometer detector) of PN obtained for the polymerizations of 2 in the presence of 4d.magnified imageGPC traces (refractometer detector) of PN obtained for the polymerizations of 2 in the presence of 4d.

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Vinylic Polymerization and Copolymerization of Norbornene and Ethene by Homogeneous Chromium(III) Catalysts

Cited by 25 publications

References 17 publications

Metal catalysts for the vinyl/addition polymerization of norbornene

Metal catalysts for the vinyl/addition polymerization of norbornene

Ethylene Polymerization with Silica-Supported Cr[N(SiMe3)2]3/Alumoxane Catalyst

Grafting of Vinyl‐Type Polynorbornene on Polybutadiene and Polyisoprene

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