Kinetic Modeling of 1-Hexene Polymerization Catalyzed by Zr(tBu-ONNMe2O)Bn2/B(C6F5)3

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• 作者：Jeffrey M. Switzer ; Nicholas E. Travia ; D. Keith Steelman ; Grigori A. Medvedev ; Kendall T. Thomson ; W. Nicholas Delgass ; Mahdi M. Abu-Omar ; James M. Caruthers
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：June 26, 2012
• 年：2012
• 卷：45
• 期：12
• 页码：4978-4988
• 全文大小：438K
• 年卷期：v.45,no.12(June 26, 2012)
• ISSN：1520-5835

文摘

Kinetic modeling using a population balance approach has been performed in order to identify a mechanism and a set of rate constants that describe the batch polymerization of 1-hexene by the homogeneous single-site catalyst Zr(tBu-ON^NMe₂O)Bn₂ activated by B(C₆F₅)₃ in toluene. The mechanism and rate constants were determined by making use of a multiresponse data set, including (i) monomer concentration versus time for various initial concentrations of monomer and catalyst, (ii) the time evolution of the molecular weight distribution, (iii) active site concentrations versus time, and (iv) vinyl end group concentrations versus time. The overall mechanism requires slow chain initiation compared to propagation, 2,1-misinsertion and recovery, and two chain transfer pathways鈥攐ne forming vinylidene end groups and the other forming vinylene end groups. The quantitative analysis of kinetic data clearly shows that a significant fraction of the catalyst does not participate in the chain growth process. The quantitative analysis is carefully detailed to provide a general procedure for kinetic model discrimination and the assignment of rate constants that can be used for other single-site catalysts.