Quantitative Modeling of the Temperature Dependence of the Kinetic Parameters for Zirconium Amine Bis(Phenolate) Catalysts for 1-Hexene Polymerization

The chemical kinetics for a series of three zirconium amine bis(phenolate) catalysts for poly 1-hexene polymerization have been examined as a function of temperature. Detailed modeling of the experimental data has yielded the activation parameters for many of the reaction rate constants, including those for propagation, initiation, chain transfer, and monomer misinsertion and recovery. While existing literature is sparse, the results herein generally agree with previously published values, specifically that for the propagation rate constant the magnitude of the enthalpy of activation is low (12 kcal mol−1 and below), and the magnitude of the entropy of activation is moderate (up to −27 cal mol−1 K−1). With regard to the remaining rate constants, Arrhenius behavior is observed in most cases despite the complexity of the temperature dependence in the two step adsorption/insertion kinetics. The rate expression for these reactions approaches an Arrhenius form in certain limiting cases of the relative elementa...