Comparison of Selected Zirconium and Hafnium Amine Bis(phenolate) Catalysts for 1-Hexene Polymerization

Autor:	James M. Caruthers, Jeffrey M. Switzer, Silei Xiong, D. Keith Steelman, Paul D. Pletcher, W. Nicholas Delgass, Mahdi M. Abu-Omar, Grigori A. Medvedev
Rok vydání:	2013
Předmět:	Zirconium Organic Chemistry Inorganic chemistry chemistry.chemical_element Hafnium Inorganic Chemistry 1-Hexene chemistry.chemical_compound Monomer Reaction rate constant chemistry Polymerization Pyridine Polymer chemistry Amine gas treating Physical and Theoretical Chemistry
Zdroj:	Organometallics. 32:4862-4867
ISSN:	1520-6041 0276-7333
Popis:	The kinetics of 1-hexene polymerization using a family of three zirconium and hafnium amine bis-phenolate catalysts, M[t-Bu-ONXO]Bn2 (where M = Zr (a) or Hf (b), and X = THF (1), pyridine (2), or NMe2 (3)), have been investigated to uncover the mechanistic effect of varying the metal center M. A model-based approach using a diverse set of data including monomer consumption, evolution of molecular weight, and end-group analysis was employed to determine each of the reaction-specific rate constants involved in a given polymerization process. This study builds upon the mechanism of polymerization for 1a–3a, which has been previously reported by applying the same methodology to the hafnium containing analogues, 1b–3b. It has been observed that each elementary step-specific rate constant that involves the insertion of a monomer is reduced by an order of magnitude. As previously reported for catalysts 1a–3a, a quantitative structure–activity relationship was uncovered between the logarithm of the monomer-indepe...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::2b6ec42c3d1f20f9b43512bd23555df6 https://doi.org/10.1021/om4006005 Zobrazit plný text záznamu