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A Kinetic Investigation of the Initialization of Catalyzed Chain Growth of Styrene: The Reaction of Cp* 2 ZrCl 2 with Dibenzylmagnesium
Author(s) -
Primpke Sebastian,
Deinert Adrian,
Ehlers Florian,
Vana Philipp
Publication year - 2014
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201300710
Subject(s) - chemistry , catalysis , styrene , toluene , kinetic energy , kinetic resolution , initialization , polymer chemistry , chain transfer , kinetic scheme , adduct , copolymer , organic chemistry , enantioselective synthesis , radical polymerization , physics , quantum mechanics , computer science , programming language , polymer
The system Cp* 2 ZrCl 2 and dibenzyl magnesium in toluene, which is a model system for initialization in the catalyzed chain growth (CCG) of styrene using a bifunctional organometallic chain transfer agent, is studied via time‐resolved NMR spectroscopy. Based on these data, a mechanism of initialization is proposed. The experimental concentration profiles of the individual species can successfully be modeled to the proposed kinetic scheme. Refined kinetic coefficients of high significance can be obtained by applying analytical methods using pseudo‐first‐order rate approximations. It is found that the adduct of the Zr catalyst and the Mg compound only slowly transforms via a ligand exchange reaction, yielding the alkylated Zr species. The temperature dependence of these reactions indicates a high reaction barrier of this type of rearrangement, which constitutes the core reaction of CCG in terms of molecular‐weight control.