Abstract: The family of highly active ethylene polymerization catalysts based on the complexes of transition metals with bis(imino)pyridine ligands has been intensively studied in the last ten years. In this study we summarize the known data and present new kinetic results on the ethylene polymerization over homogeneous catalysts based on Fe(II), Co(II), V(III) and Cr(III) bis(imino)pyridine complexes with close ligand framework (2,6-(2,4,6-R3LMeCln, where R= H, Me, i-Pr, t-Bu, L=(C6H3N=CMe)2C5H3N, M= Fe(II), Co(II), V(III), Cr(III), n=2,3). The effects of the activator nature (different samples of methylalumoxane (MAO), or aluminium trialkyls) and polymerization conditions on the activity of these complexes and the resulted PE structure (molecular weight, molecular weight distribution, content of methyl and vinyl groups) have been studied. For the first time the number of active centers and propagation rate constant for ethylene polymerization with Fe(II), Co(II), Cr(III) and V(III) bis(imino)pyridine complexes, activated with MAO and Al(i-Bu)3, have been determined using method of polymerization inhibition by radioactive carbon monoxide (14CO). The experimental data obtained in comparable conditions have shown that the catalytic properties of bis(imino)pyridine complexes ( polymerization activity, number of active centers and propagation rate constant, copolymerization reactivity, composition of optimal activator, formation of single site or multiple sites catalytic system, catalysts thermal stability and PE structure) are mainly determined by transition metal center of complex. The size of the substituents R in 2,6-positions of arene ring in the ligand L affects the number of active centers and molecular weight of PE as well.

Cite: Semikolenova N.V. , Barabanov A.A. , Echevskaya L.G. , Matsko M.A. , Zakharov V.A.
Homogeneous catalysts based on bis(imino)pyridine complexes of iron, cobalt, vanadium and chromium: The kinetic peculiarities of ethylene polymerization
Monography chapter Homogeneous Catalysts: Types, Reactions and Applications. – Nova Science Publishers, Inc.., 2011. – C.97-126. – ISBN 9781611228946. Scopus РИНЦ

Identifiers:

Scopus:	2-s2.0-84895294777
Elibrary:	21881845

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