The homopolymerization of ethylene by using different catalytic systems based on dinitro-substituted bis(salicylaldiminate)nickel(II) precursors such as bis[3,5dinitro-N(2,6-diisopropylphenyl)]nickel(II) and bis[3,5-dinitro-N(phenyl)]nickel(II) in combination with organoaluminum compounds was investigated. In particular, the catalytic performances were studied as a function of the main reaction parameters, such as temperature, pressure, Al/Ni molar ratio, and duration. Methylaluminoxane resulted in the best co-catalyst. Activities up to 200 kg polyethylene/(mol Ni X h) to give a linear high-molecular-weight polymer were achieved. The influence of the bulkiness of the substituents on the N-aryl group of the aldimine ligand was also checked; it resulted in a determinant for catalytic activity rather than for polymer characteristics. (C) 2004 Wiley Periodicals, Inc.
|Autori:||CARLINI C; A. MACINAI; F. MASI; A.M. RASPOLLI GALLETTI; R. SANTI; G. SBRANA; A. SOMMAZZI|
|Titolo:||Ethylene polymerization by bis(salicylaldiminate)nickel(II)/Aluminoxane catalysts|
|Anno del prodotto:||2004|
|Digital Object Identifier (DOI):||10.1002/pola.20102|
|Appare nelle tipologie:||1.1 Articolo in rivista|