Precise Active Site Analysis for TiCl3/MgCl2 Ziegler-Natta Model Catalyst Based on Fractionation and Statistical Methods

Catalysts

Shougo Takahashi¹  Toru Wada¹  Toshiaki Taniike¹ 

[1] School of Materials Science, Japan Advance Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan;

关键词: Ziegler-Natta catalysts;    propylene polymerization;    model catalyst;    active site;    two-site model analysis;   

DOI  :  10.3390/catal3010137

来源: mdpi

【 摘 要 】

In heterogeneous Ziegler-Natta catalysts for olefin polymerization, isolation of a single type of active sites is a kind of ambition, which would solve long-standing questions on the relationship between active site and polymer structures. In this paper, polypropylene produced by TiCl₃/MgCl₂ model catalysts with minimum Ti heterogeneity was analyzed by combined solvent fractionation and the two-site statistical model. We found that the active sites of the model catalysts were classified into only three types, whose proportions were dependent on the Ti dispersion state. The addition of external donors not only newly formed highly isospecific sites, but also altered the stereochemical nature of the other active sites.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.