Oligomerization of ethylene with soluble transition-metal catalysts

Henrici‐Olivé, G.; Olivé, S.

doi:10.1007/3-540-06910-0_1

Cited by 53 publications

(5 citation statements)

References 23 publications

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“…All of the complexes displayed high catalytic activities for ethylene oligomerization with high α-olefin selectivity (>99%) at 30 atm of ethylene pressure. The distribution of obtained oligomers resembled Schulz−Flory rules, and the probability of chain propagation is represented with the constant K , where K = rate of propagation/((rate of propagation) + (rate of chain transfer)) = (moles of C n +2 )/(moles of C n ); the K values are determined by the molar ratio of C 12 and C 14 fractions . The distribution of the oligomers (entries 4−6 of Table ) are shown in detail in Figure .…”

Section: Resultsmentioning

confidence: 92%

Iron(II) and Cobalt(II) 2-(Benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl Complexes as Catalysts for Ethylene Oligomerization and Polymerization

et al. 2007

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A series of iron(II) (7a-11a) and cobalt(II) (7b-11b) 2-(1-methyl-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl complexes were synthesized, as well as bidentate iron(II) and cobalt(II) complexes ligated by 2-(2-benzimidazolyl)-6-methylpyridine, 2-(carboethoxyl)-6-(2-benzimidazolyl)pyridine, and 2-(1methyl-2-benzimidazolyl)-6-acetylpyridine. All organic compounds were fully characterized by NMR and IR spectroscopy and elemental analysis, while the metal complexes were carefully examined by IR spectroscopy and elemental analysis. Their molecular structures were determined by single-crystal X-ray diffraction analysis. The bidentate metal complexes display a distorted-tetrahedral coordination geometry; however, 2a is an exception, with a distorted-trigonal-bipyramidal geometry due to coordination of one DMF molecule. The X-ray crystallographic studies on all of the tridentate metal complexes revealed the coordination geometry as a distorted trigonal bipyramid. Upon activation with MAO or MMAO, the iron(II) 2-(2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl complexes showed high activities with good R-olefin selectivity, while the cobalt(II) analogues displayed moderate to good catalytic activities. However, other bidentate metal complexes showed considerable moderate catalytic activity. The oligomers and polyethylene waxes obtained were R-olefins, and the distribution of oligomers resembled Schulz-Flory rules with some exceptions. Various reaction parameters were investigated, and the results revealed that both the steric and electronic effects of ligands affect the catalytic activities of their metal complexes as well as the distribution of products.

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Section: Resultsmentioning

confidence: 92%

Iron(II) and Cobalt(II) 2-(Benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl Complexes as Catalysts for Ethylene Oligomerization and Polymerization

et al. 2007

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“…The detailed results are summarized in Table . The distribution of oligomers obtained in all cases follows Schulz−Flory rules, which is characteristic of the constant α, where α represents the probability of chain propagation (α = rate of propagation/((rate of propagation) + (rate of chain transfer)) = (moles of C n +2 )/(moles of Cn)) . The α values are determined by the molar ratio of C 12 and C 14 fractions.…”

Section: Resultsmentioning

confidence: 99%

Iron Complexes Bearing 2-Imino-1,10-phenanthrolinyl Ligands as Highly Active Catalysts for Ethylene Oligomerization

Sun¹,

Jie²,

Zhang³

et al. 2005

Organometallics

164

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A series of iron complexes ligated by 2-imino-1,10-phenanthrolinyl ligands, LFeCl 2 (L ) 2-(ArNd CR)-1,10-phen), were synthesized and sufficiently characterized by elemental and spectroscopic analysis along with X-ray diffraction analysis. Activated with methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), these iron(II) complexes show high catalytic activities up to 8.95 × 10 7 g mol -1 (Fe) h -1 for ethylene oligomerization. The distribution of oligomers produced follows Schluz-Flory rules with high selectivity for R-olefins. Both the steric and electronic effects of coordinative ligands affect the catalytic activity and the properties of the catalytic products. The parameters of the reaction conditions were also investigated to explore the catalytic potentials of these complexes.

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“…Compared with 1 and 3 , in which both ortho positions of the aryl rings are substituted by bromo and chloro groups, respectively, the iron complexes with only one ortho substituent on the aryl rings, 5 and 7 , show lower activity and provide much lower molar mass products in the ethylene polymerization. The distribution of oligomers obtained by 5 and 7 follows Schulz−Flory rules, which can be characterized by a constant α, where α represents the probability of chain propagation [α = rate of propagation/(rate of propagation + rate of chain transfer) = mol of C n +2 /mol of C n ]. − The α value can be determined by the molar ratio of C 12 and C 14 fractions. Under the conditions of 0 °C, 1 atm, and Al/Fe molar ratio of 1250, the activities of mono ortho -substituted complexes 5 and 7 (6.0 × 10 6 and 4.3 × 10 6 g/mol of cat·h) are about half of the corresponding double ortho- substituted complexes 3 (12.8 × 10 6 g/mol of cat·h) and 1 (8.6 × 10 6 g/mol of cat·h).…”

Section: Resultsmentioning

confidence: 99%

Halogen-Substituted 2,6-Bis(imino)pyridyl Iron and Cobalt Complexes: Highly Active Catalysts for Polymerization and Oligomerization of Ethylene

et al. 2003

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A series of halogen-substituted 2,6-bis(imino)pyridyl ligands and their iron and cobalt complexes [{2,6-(2,6-X1X2C6H3NCCH3)2C5H3N}MCl2] (X1 = X2 = Br, M = Fe (1), Co (2); X1 = X2 = Cl, M = Fe (3), Co (4); X1 = Cl, X2 = H, M = Fe (5), Co (6); X1 = Br, X2 = H, M = Fe (7), Co (8); X1 = I, X2 = H, M = Fe (9), Co (10)) and [M{2,6-(2,6-X1X2C6H3NCCH3)2C5H3N}2]2+[MCl4]2- (X1 = F, X2 = H, M = Fe (11)) have been synthesized. The molecular structures of complexes 1, 8, 9, 10, and 11 were determined by X-ray diffraction. Crystallographic analyses indicate that 1, 8, 9, and 10 are five-coordinate complexes, while 11 is an ion-pair complex with one six-coordinate iron center and one four-coordinate iron center. These metal coordinative complexes, activated by modified methylaluminoxane (MMAO), lead to highly active ethylene polymerization and/or oligomerization catalysts. The catalyst productivity and product properties crucially depended on the metal center and the halogen substituents on the aryl rings. The catalyst productivities are in the range of (0−73.0) × 106 g/mol of cat·h. The species 11, having ion-pair structure, is inactive. In particular, the product molar masses were changed from high molar mass (M w of 377 000) to low molar mass oligomers by varying the halogen substituents. NMR and thermal analyses reveal the polymer is highly linear. The oligomer products follow a Schulz−Flory distribution with high selectivity for linear α-olefins. The effects of reaction condition on the polymerization and oligomerization have also been studied.

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Oligomerization of ethylene with soluble transition-metal catalysts

Cited by 53 publications

References 23 publications

Iron(II) and Cobalt(II) 2-(Benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl Complexes as Catalysts for Ethylene Oligomerization and Polymerization

Iron(II) and Cobalt(II) 2-(Benzimidazolyl)-6-(1-(arylimino)ethyl)pyridyl Complexes as Catalysts for Ethylene Oligomerization and Polymerization

Iron Complexes Bearing 2-Imino-1,10-phenanthrolinyl Ligands as Highly Active Catalysts for Ethylene Oligomerization

Halogen-Substituted 2,6-Bis(imino)pyridyl Iron and Cobalt Complexes: Highly Active Catalysts for Polymerization and Oligomerization of Ethylene

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