Unique catalytic behavior of chromium complexes having halogenated bis(imino)pyridine ligands for ethylene polymerization

Nakayama, Yuushou; Sogo, Kenji; Yasuda, Hajime; Shiono, Takeshi

doi:10.1002/pola.20767

Cited by 49 publications

(38 citation statements)

References 33 publications

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“…These phenomena demonstrated polyethylenes Table 3 Oligomerization and polymerizatiom with C1/MMAO at 1 atm ethylene a Entry Al/ Cr containing different components had broad molecular weight distributions, which were concurrent with the results observed for chromium(III) complexes supported by bis(2-pyridylmethyl)amines [33]. Such phenomena of multiple endothermic peaks in polyolefin have also observed in our previous research [28] and literatures [34][35][36][37][38]. The broad molecular weight distribution of polymers was in agreement with that of oligomers.…”

Section: 22supporting

confidence: 87%

Chromium(III) complexes ligated by 2-(1-isopropyl-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines: Synthesis, characterization and their ethylene oligomerization and polymerization

Chen

Zuo

Peng

et al. 2008

Journal of Organometallic Chemistry

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Section: 22supporting

confidence: 87%

Chromium(III) complexes ligated by 2-(1-isopropyl-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines: Synthesis, characterization and their ethylene oligomerization and polymerization

Chen

Zuo

Peng

et al. 2008

Journal of Organometallic Chemistry

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“…The molecular weight of resulting polymers increased with increasing Al/Cr molar ratio. This result is in disagreement with that reported for Fe(II), Co(II) and Cr(III) catalysts [25,26]. The molecular weights of the resulting polymers increased with increasing Al/Cr ratio, so there is probably no chain transfer to aluminum in the 2/Cr(III)/MAO catalytic system for the tetramerization of ethylene.…”

Section: Characterization Of Polyethylenecontrasting

confidence: 56%

Ethylene tetramerization with a highly active and long-lifetime trinuclear diphenylphosphinoamine/Cr(III)/MAO catalyst

et al. 2012

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The synthesis and characterization of a novel trinuclear diphosphinoamine ligand 2 are reported. The ligand combined with Cr(III), activated with methylaluminoxane, lead to highly active and long-lifetime catalytic systems for the tetramerization of ethylene to form 1-octene. The effects of reaction temperature, reaction pressure, molar ratio of Al/Cr and bis(diphenylphosphino)amine/Cr on the catalytic activity and product selectivity were studied. Compared with its mononuclear analogue 1, ligand 2 showed a higher catalytic activity and longer lifetime for ethylene tetramerization in the presence of methylaluminoxane as cocatalyst. High molecular weight polyethylene was generated as a by-product with extremely broad molecular weight distributions. In recent years there has been a substantial acceleration in research activity concerned with homogeneous transition metal catalysts for ethylene oligomerization and polymerization. Chromium catalysts play an important role in both of these processes [1][2][3][4][5][6][7][8]. Since the first report of ethylene tetramerization to form 1-octene using Cr-bis(diphenylphosphino)amine (PNP) catalysts [9], numerous studies have investigated the relationship between ligand structure and catalytic properties. We were attracted by the potential for using chromium as an ethylene tetramerization active center because of its high catalytic activity and high selectivity to 1-octene. Here, we describe a new trinuclear PNP ligand that displays higher activity and a long lifetime for ethylene tetramerization to 1-octene.

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“…2 ), has been prepared by a related route [71] . Symmetrical 2,6-bis(alkylimino)pyridines, [2,6-(R'N=CR) 2 C 5 H 3 N] ( 4 R′ = alkyl), can be prepared using the general route employed for 1 [22,45,72,73] .…”

Section: Ligand Preparationmentioning

confidence: 99%

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

Gibson¹,

Solan²

2008

Topics in Organometallic Chemistry

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This chapter describes the brief history of iron or cobalt catalysts for olefin polymerisation and oligomerisation. Since the discovery in 1998 that 2,6-bis(imino)pyridine iron and cobalt halides, on activation with MAO, can convert ethylene to highly linear polyethylene, numerous reports have been concerned with ligand modification, mechanisms for precatalyst activation, identifying the active species and understanding the mode of propagation/chain transfer. In addition, heterogenisation of this class of catalysts, their incorporation into macrocycles/ polymers and their use in reactor blending/tandem catalysis has seen some important developments; alternative ligand architectures that can support active iron and cobalt catalysts are also discussed as are different types of olefinic monomer.

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Unique catalytic behavior of chromium complexes having halogenated bis(imino)pyridine ligands for ethylene polymerization

Cited by 49 publications

References 33 publications

Chromium(III) complexes ligated by 2-(1-isopropyl-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines: Synthesis, characterization and their ethylene oligomerization and polymerization

Chromium(III) complexes ligated by 2-(1-isopropyl-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines: Synthesis, characterization and their ethylene oligomerization and polymerization

Ethylene tetramerization with a highly active and long-lifetime trinuclear diphenylphosphinoamine/Cr(III)/MAO catalyst

Iron-Based and Cobalt-Based Olefin Polymerisation Catalysts

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