Detailed Kinetics of 1-Hexene Oligomerization Reaction with (n-Bu-Cp)2ZrCl2-MAO Catalyst

The paper describes a kinetic study of 1-hexene oligomerization reaction with the (n-BuCp)(2)ZrCl2-MAO catalyst system at 70 degrees C. GC analysis of the monomer/oligomer mixtures at different reaction times in the course of a 5-h reaction, provided information on the formation rates of individual oligomer molecules, from the 1-hexene dimer, C12H24, to the tetradecamer, C84H168. Kinetic modeling of the oligomerization kinetics strongly supports the principal premise of polymerization kinetics, that the value of the propagation rate constant of the chain growth reaction does not depend on the number of monomer units in Me growing polymer chain. The only exception from this rule is the insertion of a 1-hexene molecule into the Zr+-C bond in the active center bearing a single monomer unit, (n-Bu-Cp)(2)Zr+-CH2-CH2-C4H9. The rate constant of this reaction in one order of magnitude is higher than the rate constant of 1-hexene insertion into active centers which are P-branched with respect to the Zr atom, (n-Bu-Cp)(2)Zr+-[CH2-CH(C4H9)](n)-CH2-CH2-C4H9.