Bis-(cyclopentadienyl)-titanium Dichloride-Alkylaluminum Complexes as Soluble Catalysts for the Polymerization of Ethylene<sup>1,2</sup>

Breslow, David S.; Newburg, Norman R.

doi:10.1021/ja01510a018

Cited by 243 publications

(43 citation statements)

References 3 publications

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“…[24,25] Several stable Al-Ti bimetallic analogues of 25 were reported to be highly active for olefin polymerization. [47,49,50] It is worth mentioning that 23 is actually a twin-site involving two neighboring poorly isospecific propagation centers. The bimetallic complexing during the pretreatment might deactivate one of the two centers [11,51] and consequently the other propagation center is transferred into highly isospecific (28) (reaction (9) in Scheme 2).…”

Section: Dynamic Formation Deactivation and Transformation Of Stereomentioning

confidence: 99%

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl₄/MgCl₂ Ziegler‐Natta Catalyst

Liu

Nitta

Nakatani

et al. 2002

Macro Chemistry & Physics

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The formation, deactivation and transformation of stereospecific active sites on the donor‐free TiCl4/MgCl2 catalyst induced by short time reaction with triethylaluminium (TEA) cocatalyst (pretreatment time: 0 ∼ 60 s) were investigated by stopped‐flow propylene polymerization combined with temperature rising elution fractionation (TREF) and gel permeation chromatography (GPC) methods. We got the first report that the origin of isospecificity of active sites derived from the catalyst substrate and cocatalyst were individually observed without and with TEA pretreatment, respectively. Based on the three‐sites model of Corradini and Busico et al., a plausible mechanism of the formation and transformation of stereospecific active sites was proposed using active sites models in terms of specified roles of Al‐alkyl cocatalyst. It was demonstrated that the introduction of bulky alkyl groups instead of chlorine atoms into the neighborhood of active sites seems to be crucial for the generation of active sites with the highest isospecificity. magnified image

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Section: Dynamic Formation Deactivation and Transformation Of Stereomentioning

confidence: 99%

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl₄/MgCl₂ Ziegler‐Natta Catalyst

Liu

Nitta

Nakatani

et al. 2002

Macro Chemistry & Physics

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“…It has been reported that the modification in nature and number of substituents on a cyclopentadienyl ring [15][16][17][18]14,19] may directly affect the catalytic activity and/or the stereoselectivity [20], allowing the use of these metallocenic catalysts in industrial processes on a macroscale level, registering catalytic activity values similar or superior to those obtained with the conventional Ziegler-Natta heterogeneous catalysts [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

A new series of zirconium metallocenes derived from partially alkylated s-indacene with potential applications in the polymerization of ethylene

Araneda

Morales-Verdejo

Adams

et al. 2015

Inorganica Chimica Acta

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“…Newburg, Long and Breslow [99,100] suggested that the active agent was a highly polarised bimetallic species (15) containing Ti and Al bridged by chlorine (Scheme 1).…”

Section: Historical Backgroundmentioning

confidence: 99%

Group 4 metal complexes for homogeneous olefin polymerisation: a short tutorial review

2015

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The discovery of transition metal-catalysed polymerisation of olefins in the 1950s by Ziegler and Natta was of huge importance. Over the last 30 years, the interest in homogenous polymerisation has not only grown but has changed focus from primarily studying the metallocene complexes of Group 4 to widespread exploration of postmetallocene systems. This is a consequence of extensive patenting of the metallocene catalyst systems, as well as for general interest in the improvement of polyolefin catalysis. The plastics industry produces more than 10 7 tonnes of polyethylene, polypropylene and polystyrene each year worldwide, and the study of well-defined homogenous catalysts is invaluable in uncovering the mechanism of polymerisation and the fundamental properties of the active species. This short Tutorial Review gives an overview of homogenous transition metal Ziegler-Natta catalysis in general as well as an overview of a selection of Group 4 post-metallocene catalysts. An overview of the synthesis and reactions of alkyl cations relevant to olefin polymerisation is also given. Finally, this review summarises recent advances in bimetallic catalysts for olefin polymerisation.

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Bis-(cyclopentadienyl)-titanium Dichloride-Alkylaluminum Complexes as Soluble Catalysts for the Polymerization of Ethylene^1,2

Cited by 243 publications

References 3 publications

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl₄/MgCl₂ Ziegler‐Natta Catalyst

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl₄/MgCl₂ Ziegler‐Natta Catalyst

A new series of zirconium metallocenes derived from partially alkylated s-indacene with potential applications in the polymerization of ethylene

Group 4 metal complexes for homogeneous olefin polymerisation: a short tutorial review

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Bis-(cyclopentadienyl)-titanium Dichloride-Alkylaluminum Complexes as Soluble Catalysts for the Polymerization of Ethylene1,2

Cited by 243 publications

References 3 publications

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl4/MgCl2 Ziegler‐Natta Catalyst

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl4/MgCl2 Ziegler‐Natta Catalyst

A new series of zirconium metallocenes derived from partially alkylated s-indacene with potential applications in the polymerization of ethylene

Group 4 metal complexes for homogeneous olefin polymerisation: a short tutorial review

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Bis-(cyclopentadienyl)-titanium Dichloride-Alkylaluminum Complexes as Soluble Catalysts for the Polymerization of Ethylene^1,2

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl₄/MgCl₂ Ziegler‐Natta Catalyst

Specific Roles of Al‐Alkyl Cocatalyst in the Origin of Isospecificity of Active Sites on Donor‐Free TiCl₄/MgCl₂ Ziegler‐Natta Catalyst