Polymerization of ethylene using unsymmetric (α-Diimine)Ni(Ⅱ) and Pd(Ⅱ) catalysts

Abstract

This thesis deals with ethylene polymerization using new (α-diimine) nickel(Ⅱ) and palladium(Ⅱ) catalysts. New diimine ligands having tri and pentacyclic structures were synthesized via condensation reaction of phenanthrenequinone and 2,6-dialkyl aniline catalyzed with $TiCl_4/DABCO$. The α-diimine ligands were combined with four kinds of palladium precursors to form new (α-diimine) palladium catalysts. New unsymmetric diimines were also synthesized via sequential imination reaction of phenanthrenequinone and aniline derivatives. These new unsymmetrical ligands were reacted with nickel precursor to form new (α-diimine) nickel(Ⅱ) catalysts. These (α-diimine) nickel(Ⅱ) and palladium(Ⅱ) catalysts were subjected to ethylene polymerizations with different cocatalysts. In ethylene polymerization, the (α-diimine) nickel(Ⅱ) catalysts produced polyethylenes with various molecular weight depending on their ligand structure, temperature, the amount of cocatalyst. However, the (α-diimine) palladium(Ⅱ) catalysts showed no activities in ethylene polymerization even at high ethylene pressure.