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Bis(benzothiazolyl) titanium, zirconium and vanadium complexes as catalysts for ethylene polymerization
Ist Teil von
European polymer journal, 2015-07, Vol.68, p.385-397
Ort / Verlag
Elsevier Ltd
Erscheinungsjahr
2015
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
[Display omitted]
•Ti, Zr and V complexes with heterocyclic chelating ligands.•Catalytic ethylene polymerization.•Influence of the bridging moiety in the ligand on the catalyst performance.•Bimodal and multimodal resins.•Access to single-reactor polyethylene technology.
13 titanium, zirconium and vanadium complexes with 1,1-bis(benzothiazolyl)methane, 1,2-bis(benzothiazolyl)-ethane, 1,2-bis(benzothiazolyl)benzene and 2,6-bis(benzothiazolyl) pyridine ligands were synthesized and characterized. After activation with methylalumoxane (MAO), these complexes proved as good catalysts for ethylene polymerization in spite of the hetero atoms in the catalyst molecules and the oxophilicity of the metals. Structure–property-relationship studies indicated that the bridging unit connecting the two heterocyclic moieties has a strong influence on the performance of the catalysts. Different interactions of the catalyst cation and the bulky MAO anion, due to the various hetero atoms, could be responsible for this behavior. The produced polyethylenes show bimodal or multimodal molecular weight distributions indicating more than one active site in the polymerization process. Therefore such mononuclear catalysts are good candidates for single-reactor bimodal or multimodal polyethylene technology. The polymerization activity of the catalyst system [1,2-bis(benzothiazolyl)benzene zirconium tetrachloride] 13/MAO was investigated under different polymerization conditions.