N-substituted diphosphinoamines: Toward rational ligand design for the efficient tetramerization of ethylene

Kuhlmann, Sven; Blann, Kevin; Bollmann, Annette; Dixon, J; Killian, Esna; Maumela, Munaka C.; Maumela, Hulisani; Morgan, D. H.; Pretorius, Marié; Taccardi, Nicola; Wasserscheid, Peter

doi:10.1016/j.jcat.2006.10.020

Cited by 96 publications

(59 citation statements)

References 14 publications

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“…A novel trinuclear diphosphinoamine ligand was synthesiz- Figure 3 13 C NMR spectra of PE byproducts. ed and characterized.…”

Section: Resultsmentioning

confidence: 99%

“…High temperature 13 C NMR spectroscopy for the PE sample listed in entry 3 of Table 4 was also performed (Figure 3). The NMR spectrum of polyethylene presented in Figure 3 is in good agreement with a highly linear polyethylene.…”

Section: Characterization Of Polyethylenementioning

confidence: 99%

“…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. These include investigations into various single-site PNP ligands, wherein alkyl [10][11][12], cycloalkyl [13], ether [14], thioether, pyridyl tethers [15] and aryl [16,17] substituents attached to the N or P atom of the ligand backbone were synthesized and evaluated. Several dual-site PNP ligands [12,18] and a triple-site [19] were also found to have moderate activity and selectivity toward 1-octene in ethylene tetramerization.…”

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confidence: 99%

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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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“…A novel trinuclear diphosphinoamine ligand was synthesiz- Figure 3 13 C NMR spectra of PE byproducts. ed and characterized.…”

Section: Resultsmentioning

confidence: 99%

Section: Characterization Of Polyethylenementioning

confidence: 99%

mentioning

confidence: 99%

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

et al. 2012

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“…The PNP compounds with 3-and 4-methoxyphenyl groups at the P atom also function as the catalyst ligand for ethylene tetramerization. The ligands with varieties of N-substituents have been examined for the catalyst (Table 5.3, runs 1-12) [129][130][131]. The catalysts with an N-H group afford a mixture of a-olefins with broad distribution, without specific selectivity for C6 and C8, probably due to the deprotonation of NH group.…”

Section: Effect Of Ligand Structurementioning

confidence: 99%

“…Activity and selectivity of the Cr catalyst of bis(diphenylphosphino)amine ligand with an N-cycloalkyl substituent are affected by its ring size [130]. The catalysts with smaller size ring (cyclopropyl and cyclobutyl) at the N atom cause lower a-selectivity for both C6 and C8 products with lower productivity (Table 5.3, runs 10, 11), whereas the increased a-selectivity and higher productivity are achieved as increasing the ring size of the substituents (Table 5.3, runs [12][13][14].…”

Section: Effect Of Ligand Structurementioning

confidence: 99%

Oligomerization of Olefins

Takeuchi

Osakada

2014

Organometallic Reactions and Polymerization

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This article reviews recent studies on oligomerization of olefins catalyzed by transition metal complexes. Ni, Pd, and Fe complexes, having a ligand with a similar structure to the ethylene polymerization catalyst but with less bulky substituents, convert ethylene to the oligomers as a mixture with various chain lengths with Schulz-Flory molecular weight distribution. Cossee-type insertion of ethylene into the M-C bond and frequent elimination of a-olefins are proposed as the major reaction mechanism. The reaction using the Fe catalyst for polymerization and large excess of chain transfer reagents such as ZnEt 2 can yield the oligomers with Poisson distribution. Cr complexes with various ligands promote selective trimerization and/or tetramerization of ethylene to produce 1-hexene and/ or 1-octene. The mechanism involving metallacycle is proposed to account for the selectivity. Several Ti and Ta complexes are also effective for the trimerization of ethylene. Oligomerization of a-olefins has been also studied, although the product is frequently composed of branched oligomers and/or inner olefins.

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Transition Metal Catalyzed Olefin Oligomerization

Leeuwen

Chadwick

2011

Homogeneous Catalysts

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N-substituted diphosphinoamines: Toward rational ligand design for the efficient tetramerization of ethylene

Cited by 96 publications

References 14 publications

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

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

Oligomerization of Olefins

Transition Metal Catalyzed Olefin Oligomerization

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