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Preparation, characterization and testing of Cr/AlSBA-15 ethylene polymerization catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
43734 45986 2007 10 PDF Available
Title
Preparation, characterization and testing of Cr/AlSBA-15 ethylene polymerization catalysts
Abstract

Ethylene polymerization catalysts have been prepared by grafting chromium(III) acetylacetonate onto AlSBA-15 (Si/Al = ∞, 156, 86 and 30) mesoporous materials. A combination of XRD, nitrogen adsorption, TEM, ICP-atomic emission spectroscopy, H2-TPR, TGA, UV–vis and FT-IR spectroscopy, were used to characterize the prepared Cr–AlSBA-15 catalysts. By reducing the Si/Al ratio of the AlSBA-15 supports increases the amount of chromium anchored, promotes the stabilization of chromium species as chromate and decreases the reduction temperature of Cr6+ ions determined by H2-TPR. Attachment of Cr species onto AlSBA-15 surface results from the interaction of hydroxyl groups with the acetylacetonate ligands through H-bonds. On the contrary, a ligand exchange reaction may occur over siliceous SBA-15.The polymerization activity of Cr–AlSBA-15 catalysts is significantly improved by increasing aluminium content of the AlSBA-15 supports. Particularly, the chromium catalyst prepared with AlSBA-15 (Si/Al = 30) support is almost four times more active than a conventional Cr/SiO2 Phillips catalyst. Polymers obtained with all the catalysts showed melting temperatures, bulk densities and high load melt indexes indicating the formation of linear high-density polyethylene.

Graphical abstractEthylene polymerization catalysts have been prepared by grafting chromium(III) acetylacetonate onto AlSBA-15 mesoporous materials. Attachment of Cr species onto AlSBA-15 surface results from the interaction with of hydroxyl groups, while a ligand exchange reaction may occur over siliceous SBA-15. Cr–AlSBA-15 catalyst with a Si/Al = 30 is almost four times more active than a conventional Cr/SiO2 Phillips catalyst. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Mesoporous; SBA-15; AlSBA-15; Chromium; Ethylene polymerization
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Preparation, characterization and testing of Cr/AlSBA-15 ethylene polymerization catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 316, Issue 1, 2 January 2007, Pages 22–31
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us