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Synthesis, characterization and catalytic properties for olefin polymerization of two new dimeric zirconium(IV) complexes having diamine-bis(phenolate) and chloride ligands

Paper ID Volume ID Publish Year Pages File Format Full-Text
39242 45815 2015 8 PDF Available
Title
Synthesis, characterization and catalytic properties for olefin polymerization of two new dimeric zirconium(IV) complexes having diamine-bis(phenolate) and chloride ligands
Abstract

•The new dimeric zirconium complexes bearing diamine bis(phenolate) were synthesized.•The formation of active species was followed by 1H NMR spectroscopy.•The catalytic properties in 1-olefin and ethylene polymerization were studied.•Atacticor isotactic poli(1-octene) was formed depending on the ligand structure.•PE with high or low molecular weight was produced depending on the ligand structure.

Reaction of the zirconium tetrachloride with one equivalent of the sodium salt of the diamine bis (phenolate) ligand, L1H2 (Me2NCH2CH2N-(CH2-2-OH-3,5-tBu-C6H2)2) or L2H2 (Me2NCH2CH2N-(CH2-2-OH-3,5-tBu-C6H2)(CH2-2-OH-C6H4)) in the presence of air led to formation of [Lig1ZrCl]2(μ-O) and [Lig2ZrCl]2(μ-O), respectively. These novel oxo-bridged dinuclear zirconium complexes were characterized by elemental analysis, 1H NMR spectroscopy and by single-crystal X-ray diffraction. Their reactivities in polymerization of ethylene and 1-octene, upon activation with Al(iBu)3/Ph3CB(C6F5)4 and MAO, were examined. It was found that lack of t-Bu substituents on one phenolate ring cause a significant decrease in catalytic activity but leads to polymers with improving properties, i.e., to poly(1-olefin)s with significantly higher stereoregularity and polyethylenes with higher molecular weight. In addition, the interaction of the [Lig1ZrCl]2(μ-O) precursors with MAO and with the Me3Al activator was investigated by 1H NMR spectroscopy giving an insight into the catalyst transformations in the course of the polymerization reaction.

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Keywords
Zirconium catalyst; Diamine-bis(phenolate) ligand; Ziegler–Natta polymerization; Poly(1-octene); Polyethylene
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Synthesis, characterization and catalytic properties for olefin polymerization of two new dimeric zirconium(IV) complexes having diamine-bis(phenolate) and chloride ligands
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 503, 25 August 2015, Pages 26–33
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
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Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
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