The Relationship Between Kinetics and Mechanisms

Fink, Gerhard; Herfert, Norbert; Montag, P.

doi:10.1007/978-3-642-79136-9_9

Cited by 23 publications

(22 citation statements)

References 51 publications

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“…We observed up to 40 times higher activities for a MAO-based homogeneous catalyst system. It is generally accepted that, for each catalyst precursor utilized, a different amount of MAO is required to generate cations of all of the metal centers in solution (often >1000 Al:Zr is required). − The lower productivities for polymerizations with zirconocene dichloride relative to the dimethyl precursors suggest that at an [Al]:[Zr] ratio of 90 the dimethyl compound is more efficiently converted to the active catalyst, resulting in the highest activity with MAO as cocatalyst. The protonolysis reaction of dimethylzirconocenes with the aluminum-free initiator, anilinium borate, produced the most active catalyst system we investigated.…”

Section: Discussionmentioning

confidence: 99%

Metallocene/Borate-Catalyzed Polymerization of Amino-Functionalized α-Olefins

et al. 1998

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Cationic metallocene/borate catalysts, generated from zirconocene dimethyl compounds, L n ZrMe2, and anilinium borate, [HNMe2Ph]+[B(C6F5)4]-, were used to polymerize 5-amino-1-pentenes and one 4-amino-1-butene with dimethyl, diethyl, diisopropyl, or diphenyl substitution patterns on nitrogen. The monomer 5-(N,N-diisopropylamino)-1-pentene showed the highest activity with Cp*2ZrMe2/borate and was used for all further investigations. The catalytic system Cp*2ZrMe2/borate was 4 times more active than the corresponding methylaluminoxane-based system and 180 times more active than the heterogeneous system, TiCl3/Al(i-Bu)3. 1-Hexene and 5-(N,N-diisopropylamino)-1-pentene were polymerized with Cp*2ZrMe2 and rac-ethylenebis(tetrahydroindenyl) zirconium dimethyl, rac-EB(THI)ZrMe2. Polymerization of both monomers with Cp*2ZrMe2 displayed similar activities. Hexene polymerizations with rac-EB(THI)ZrMe2 were 30 times more active than those with aminopentene. 5-(N,N-Diisopropylamino)-1-pentene polymerizations gave rise to isotactic poly(aminopentene) with C 2 symmetric catalysts, syndiotactic polymer with a C s symmetric catalyst, and atactic polymer with achiral catalyst precursors.

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Section: Discussionmentioning

confidence: 99%

Metallocene/Borate-Catalyzed Polymerization of Amino-Functionalized α-Olefins

et al. 1998

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“…This was proved by Fink et al in experiments at low pressures. [13] The polymers obtained in the polymerization tests were investigated by gel permeation chromatography (GPC), infrared spectroscopy (IR), and differential scanning calorimetry (DSC). Furthermore, melt index and density, which are important parameters for application, were measured.…”

Section: Methodsmentioning

confidence: 99%

Immobilized Metallocene Catalysts in the Polymerization of Ethylene under High Pressure

Bergemann¹,

Luft

1998

Chem. Eng. Technol.

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The review of these findings suggest that a new apparatus should still improve results with regard to the production of smaller beads, the handling of fluids of higher viscosities, the density of particle distribution, and, especially, the reduction of overall losses, hence, making this technology applicable for various industries, e.g., the manufacture of catalysts or chromatographic materials. AcknowledgementWe wish to thank Hoechst and Akzo for supplying the chemicals.

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“…A large difference in the triad tacticity of the PVC obtained in toluene and in CH 2 Cl 2 was not observed. This suggests that a contactpair species is in equilibrium with free ion pairs, and the equilibrium shifts to free ion species with increasing solvent polarity, but VC itself seems to act as a polar solvent [7].…”

Section: Polymerization In Toluenementioning

confidence: 96%

“…Deffieux and coworkers reported that enhancement of the activity for the polymerization of 1-hexene with rac-EtInd 2 ZrCl 2 /methylaluminoxane (MAO) catalyst was observed in CH 2 Cl 2 , in comparison to that in toluene [6]. Fink et al reported that the activity for the polymerization of propylene with iPr[FluCp]ZrCl 2 /MAO (FluCp ¼ fluorenyl-cyclopentadienyl) catalyst in CH 2 Cl 2 was higher than that in toluene [7]. On the other hand, the syndiotacticity of the polymer decreased upon changing the solvent from toluene to CH 2 Cl 2 .…”

Section: Introductionmentioning

confidence: 95%

“…Subsequently, it has become possible to develop an unsaturated cationic metallocene catalyst system [3][4][5]. Solvent polarity plays some roles in olefin polymerizations with metallocene catalysts, and it was reported that in the polymerization of olefins, a solvent affects not only the activity for the polymerization but also the stereoregularity of the polymers [6,7]. Deffieux and coworkers reported that enhancement of the activity for the polymerization of 1-hexene with rac-EtInd 2 ZrCl 2 /methylaluminoxane (MAO) catalyst was observed in CH 2 Cl 2 , in comparison to that in toluene [6].…”

Section: Introductionmentioning

confidence: 99%

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Polymerization of vinyl chloride with Cp*Ti(OPh)₃/MAO catalyst in toluene

Nomaguchi

Tsuchiya

Endo

2009

Vinyl Additive Technology

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Polymerization of vinyl chloride (VC) with a Cp*Ti(OPh) 3 /MAO catalyst in toluene was investigated. The polymerization rate was lower than that in CH 2 Cl 2 , and the mm triad concentration of the PVC obtained in toluene was somewhat higher than that of the PVC obtained in CH 2 Cl 2 . As the polymerization in toluene proceeded at a considerable rate, a kinetic study of this polymerization was undertaken. The polymer yield increased with reaction time, and the molecular weight of the polymer increased with increasing polymer yield. The M w /M n ratio of the polymer decreased with increasing polymerization temperature. The initiator efficiency of the catalyst was low at the initial stage of the polymerization in toluene, but it reached nearly 100% when the polymerization was carried out for more than 30 h. The control of both the molecular weight of PVC and its main-chain structure was found to be possible in the polymerization of VC with the Cp*Ti(OPh) 3 /MAO catalyst in toluene.

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The Relationship Between Kinetics and Mechanisms

Cited by 23 publications

References 51 publications

Metallocene/Borate-Catalyzed Polymerization of Amino-Functionalized α-Olefins

Metallocene/Borate-Catalyzed Polymerization of Amino-Functionalized α-Olefins

Immobilized Metallocene Catalysts in the Polymerization of Ethylene under High Pressure

Polymerization of vinyl chloride with Cp*Ti(OPh)₃/MAO catalyst in toluene

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The Relationship Between Kinetics and Mechanisms

Cited by 23 publications

References 51 publications

Metallocene/Borate-Catalyzed Polymerization of Amino-Functionalized α-Olefins

Metallocene/Borate-Catalyzed Polymerization of Amino-Functionalized α-Olefins

Immobilized Metallocene Catalysts in the Polymerization of Ethylene under High Pressure

Polymerization of vinyl chloride with Cp*Ti(OPh)3/MAO catalyst in toluene

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Polymerization of vinyl chloride with Cp*Ti(OPh)₃/MAO catalyst in toluene