A study of the elementary reactions involved in the catalytic activation process of α-diimine NiBr 2 by methylaluminoxane (MAO), for α-olefins polymerization, was undertaken in toluene and chlorobenzene as solvents. The investigation is based on the comparative study of polymerization kinetics of hex-1-ene, UV−visible spectroscopic analysis of the catalytic system and structural analysis of the poly(hex-1-ene)s formed. Correlation between polymerization activities and changes in the UV−visible absorption spectrum of the transition metal derivative were found. Spectroscopic data have underlined the important role of the monomer in the stabilization process of the nickel-based active species. Partial polymerization orders with respect to MAO, nickel derivative and monomer were determined. Surprisingly, an apparently negative monomer order of the polymerization corresponding to a decrease of the polymerization rate with an increase of monomer concentration in the reacting medium was observed. A tentative interpretation based on the presence of two types of propagating active species of different reactivity, resulting from the walking migration mechanism, is discussed.
No takes yet. Share an insight, caveat, or question.
Peruch et al. (1999) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: