In situ activation of rac-(SBI)Zr(NMe2)2 for the polymerization of propylene |
| |
Authors: | Il Kim Richard F Jordan |
| |
Affiliation: | (1) Department of Chemical Engineering, University of Ulsan, P.O. Box 18, Ulsan 680-749, Korea, KR;(2) Department of Chemistry, University of Iowa, Iowa City, IA52242, USA, US |
| |
Abstract: | Summary. Sequential NMR-scale reactions have been carried out in order to generate cationic methylzirconium complexes by the reaction
of rac-(SBI)Zr(NMe2)2 (1, SBI = Me2Si(indenyl)2) with methylaluminoxane (MAO) or various noncoordinating anions such as HNMePh2]B(C6F5)4], HNEt2Ph]B(C6F5)4], and Ph3C]B(C6F5)4]. Reaction of 40 equiv. of MAO with 1 at room temperature was leaded to the formation of stable cationic methylzirconium complexes which polymerize propylene to
isotactic polypropylene (iPP). For the activation of 1 with noncoordinating anions 1 was firstly methylated with 4 equiv. of AlMe3 to give rac-(SBI)ZrMe2
2, and then 1 equiv. of noncoordinating anions was added to the resulting solution mixture containing 2 and various aluminum complexes dissolved in CD2Cl2 solvent. Complex 2 was immediately converted to cationic methylzirconium complex rac-(SBI)Zr(μ-Me)2AlMe2]+ (3), the adduct of the base-free rac-(SBI)ZrMe]+ cation and AlMe3. Addition of small amount of liquid propylene to the NMR tube containing 3 and other byproducts was leaded to the formation of iPP showing meso pentad value of over 85%.
Received: 6 May 1997/Revised: 22 July 1997/Accepted: 28 July 1997 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|