Species on the Activated TiCl.sub.4/MgCl.sub.2 Pre-catalyst for Diene Polymerizations

Understanding the nature of the active species of the TiCl.sub.4/MgCl.sub.2 Ziegler-Natta catalyst is special important and challenge. In this work, the pre-treated TiCl.sub.4/MgCl.sub.2 pre-catalyst by heptane washing (H-Cat) and AlR.sub.3 activation (Al-Cat) were prepared and analyzed and then use...

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Bibliographic Details
Published in:Catalysis letters 2022-08, Vol.152 (8), p.2543
Main Authors: Zhang, Jun-ying, Jiang, Meng-hui, Dong, Kai-Xuan, He, Ai-hua
Format: Article
Language:English
Subjects:
Animal behavior
Butadiene
Polymerization
Titanium
Online Access:Get full text
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Summary:Understanding the nature of the active species of the TiCl.sub.4/MgCl.sub.2 Ziegler-Natta catalyst is special important and challenge. In this work, the pre-treated TiCl.sub.4/MgCl.sub.2 pre-catalyst by heptane washing (H-Cat) and AlR.sub.3 activation (Al-Cat) were prepared and analyzed and then used to conduct butadiene (Bd)-isoprene (Ip) copolymerizations. It was proved that the adsorbed Al compounds on the Al-Cat surfaces after suffering heptane washing increased with the increase in the concentration of alkylaluminium in the pre-catalyst activation process, indicating the stable absorption of Al compounds on the active species and then influencing the catalytic behavior of the active species. Correlated the titanium oxidation state and the catalytic activity, Ti.sup.3+ species were more likely the active species for Bd-Ip copolymerization. Ti.sup.3+with adsorption of AlR.sub.2Cl on Mg adjacent to the Ti species showed reduced activity and produced polymers with high trans-1,4-configuration and relatively high molecular weight (M.sub.w). This study is anxious to provide further understanding on the mechanism of conjugated diene polymerization catalyzed by heterogeneous Ziegler-Natta catalysts.
ISSN:1011-372X
DOI:10.1007/s10562-021-03836-w