High Molecular Weight Polypropylene through Specifically DesigneZirconocene Catalysts

Spaleck, Walter; Antberg, M.; Rohrmann, Jürgen; Winter, Andreas; Bachmann, Bernd; Kiprof, Paul; Behm, Joachim; Herrmann, Wolfgang A.

doi:10.1002/anie.199213471

Cited by 274 publications

(123 citation statements)

References 16 publications

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“…Unexpectedly, and in contrast to studies performed by Spaleck et al [18] hydrogenation of rac-1 provided a better pro-catalyst, namely, complex rac-2 (entry 1 versus entry 3 in Table 1). Hydrogenation of the six-membered ring markedly increased the activity of the rac isomer.…”

Section: Activity In Ethylene Polymerisationcontrasting

confidence: 68%

Toward the Prediction of Activity in the Ethylene Polymerisation of ansa‐Bis(indenyl) Zirconocenes: Effect of the Stereochemistry and Hydrogenation of the Indenyl Moiety

et al. 2015

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A combined experimental and quantum chemical study has been performed on rac‐ and meso‐[Zr{1‐Me2Si(3‐η5‐C9H5Et)2}Cl2] (rac‐ and meso‐1) and their hydrogenated forms (rac‐ and meso‐2) to understand ligand effects and guide ligand design for more active ansa‐bis(indenyl) zirconocenes for the polymerisation of ethylene. The rac‐ansa‐zirconocene rac‐[Zr(1‐Me2Si{3‐Et‐(η5‐C9H9)}2)Cl2] (rac‐2) has been prepared and fully characterised by NMR spectroscopy and elemental analysis. The molecular structure of rac‐2 has also been determined by single‐crystal XRD. The behaviour of the catalysts was analysed in the polymerisation of ethylene and higher activities were obtained for rac‐1 and its hydrogenated form rac‐2. The influence of the stereochemistry and hydrogenation of the indenyl ligand on the experimental activities has been evaluated by computational studies. The differences along the reaction pathway are dominated by changes in the relative stabilities of the catalytic intermediates. A hybrid density functional B3LYP study, in the presence of toluene as the solvent, indicates that the rac forms give rise to more active species than their meso counterparts. The hydrogenation of the rac forms is a very promising approach to increase activities in polymerisation, in contrast to the meso forms. Finally, the global mechanism rate constants for the polymerisation reaction for each metallocene were calculated by using the thermodynamic formulation of transition‐state theory to complement the computational study.

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Section: Activity In Ethylene Polymerisationcontrasting

confidence: 68%

Toward the Prediction of Activity in the Ethylene Polymerisation of ansa‐Bis(indenyl) Zirconocenes: Effect of the Stereochemistry and Hydrogenation of the Indenyl Moiety

et al. 2015

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“…c, sPP ) has been done as Equations (1) and (2): (1) (2) where $H f, iPP is the melting enthalpy of iPP (area of the melting endotherm of iPP), $H f, sPP is the melting enthalpy of sPP (area of the melting endotherm of sPP). $H [5,[23][24][25]. 'wt% iPP' and 'wt% sPP' are the mass composition of the mixture.…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

Characterization of the morphology of iPP/sPP blends with various compositions

Bourbigot¹,

Garnier²,

Revel³

et al. 2013

Express Polym. Lett.

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Abstract. The paper investigates the morphology and the structural properties of blends of isotactic polypropylene (iPP) and syndiotactic polypropylene (sPP) having different compositions using different techniques. Solid-state nuclear magnetic resonance (NMR) permits via appropriate sequence to measure the composition, conformation and dynamics, and intimacy of mixing of polymeric materials. Measurement of relaxation times gives information on local structure of phases with different mobility. The morphology is directly related to the structural organization of the blends. The crystallization rate decreases as a function of the sPP content. The minor component is dispersed as a nodule in the main component of the blend and it plays the role of nucleating agent on it. Besides, morphology changes occur for the composition 50/50 (wt/wt) of the blend iPP/sPP. Different phases are identified, namely free amorphous, constrained amorphous and crystalline regions which exhibit different molecular mobilities. It is also shown at the interphase matrix-nodules, the nodules create a constrained amorphous zone.

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“…When we started this investigation, only 2-bromoindene (2). which can be prepared by two routes, was described.…”

Section: Me Mementioning

confidence: 99%

Synthesis of [μ-methyllenebis(η5-3-tert-butyl-2-methylinden-1-yl)dichlorozirconium(IV)]

Ivchenko

Nifant’ev

et al. 2000

Russ Chem Bull

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High Molecular Weight Polypropylene through Specifically DesigneZirconocene Catalysts

Cited by 274 publications

References 16 publications

Toward the Prediction of Activity in the Ethylene Polymerisation of ansa‐Bis(indenyl) Zirconocenes: Effect of the Stereochemistry and Hydrogenation of the Indenyl Moiety

Toward the Prediction of Activity in the Ethylene Polymerisation of ansa‐Bis(indenyl) Zirconocenes: Effect of the Stereochemistry and Hydrogenation of the Indenyl Moiety

Characterization of the morphology of iPP/sPP blends with various compositions

Synthesis of [μ-methyllenebis(η5-3-tert-butyl-2-methylinden-1-yl)dichlorozirconium(IV)]

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