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Immobilization of zirconocene within silica–tungsten by entrapment: Tuning electronic effects of the support on the supported complex

Paper ID Volume ID Publish Year Pages File Format Full-Text
42598 45932 2009 9 PDF Available
Title
Immobilization of zirconocene within silica–tungsten by entrapment: Tuning electronic effects of the support on the supported complex
Abstract

The immobilization of Cp2ZrCl2 was performed by entrapment within the binary oxide SiO2–WO3 using a non-hydrolytic sol–gel route. The catalyst and oxide matrix were characterized by complementary techniques (Rutherford backscattering spectrometry, ultraviolet–visible diffuse reflectance and infrared transmission spectroscopy, differential pulse voltammetry, adsorption–desorption of N2, and X-ray diffraction). The catalyst performance in terms of catalytic activity and polymer properties was evaluated by ethylene polymerization. Catalyst characterization suggested that the entrapped complex exhibited lower Zr electronic density than the corresponding unsupported metallocene. The polymerization results also revealed that this low Zr electronic density is optimized in terms of complex activation with low MAO concentration (low [Al/Zr] ratio) and reactivity. This fine tuning results in a catalyst system that is active with a low [Al/Zr] ratio and that achieves high catalytic activity. The results demonstrate that the entrapping method allows the generation of a catalyst system in which part of the activation process is attributed to the support. In this sense, the support may partially play MAO functions by stabilizing the active catalytic species.

Graphical abstractCp2ZrCl2 was immobilized by the entrapment within the binary oxide SiO2–WO3 using a non-hydrolytic sol–gel route. The results evidence that the entrapping method generates a catalyst system in which part of the complex activation process is attributed to the support. In this sense, the support may play partially the MAO functions by stabilizing the active catalytic species.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Supported metallocene; Sol–gel; Polymerization; Polyethylene; Mixed oxides
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Immobilization of zirconocene within silica–tungsten by entrapment: Tuning electronic effects of the support on the supported complex
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 370, Issues 1–2, 30 November 2009, Pages 114–122
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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Price was $35.95
You save - $31
Price after discount Only $4.95
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