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Olefin polymerizations with zirconocene supported on SiO2 modified by MgO, NaOH and LiOH

Paper ID Volume ID Publish Year Pages File Format Full-Text
42499 45928 2009 6 PDF Available
Title
Olefin polymerizations with zirconocene supported on SiO2 modified by MgO, NaOH and LiOH
Abstract

Silica gels modified by MgO, LiOH, and NaOH, i.e., SiO2/MgO, SiO2/LiOH, SiO2/NaOH, respectively, were examined as solid supports in the ethylene and propylene polymerization reactions using dimethylsilylene-bis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride (SHIZ) as the catalyst and i-Bu3Al as the co-catalyst. All three were found to be equally effective for the former reaction, whereas activity was discrete for the latter reaction, with the order being SiO2/MgO > SiO2/LiOH > SiO2/NaOH. For the SiO2/MgO combination which showed the highest performance, BET and STEM studies indicated that Mg was evenly distributed in the silica gel. Acid–base measurements of all three solids indicated that SiO2/MgO had strongly acidic sites whereas the other two did not, and in addition, SiO2/NaOH had strongly basic sites whereas the remaining two had only weakly basic spots. These results suggested that the presence of weakly nucleophilic anionic sites is essential for high reactivity and that strongly acidic sites enhance the reactivity.

Graphical abstractSilica gels modified by MgO, LiOH and NaOH were examined as solid supports for the zirconocene-catalyzed olefin polymerization using alkylaluminium in the place of MAO and borates as co-catalysts. All three were found to be equally effective for ethylene polymerization reaction, whereas only silica gel modified by MgO showed good activity for propylene polymerization.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Polymerization; Silica support; Magnesium oxide; Surface basicity; Surface acidity
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Olefin polymerizations with zirconocene supported on SiO2 modified by MgO, NaOH and LiOH
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 368, Issues 1–2, 31 October 2009, Pages 65–70
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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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
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