Alpha-diimine palladium (II) olefin polymerization catalyst containing substituted ortho-phenyls, as well as preparation and application thereof

The invention discloses a novel post-transition metal alpha-diimine palladium (II) olefin polymerization catalyst containing substituted ortho-phenyls, wherein two large-volume groups, namely phenyls are introduced in ortho positions of an aromatic ring of nitrogen atoms of imine. As the phenyls have the larger volume, the metal center of the catalyst can be effectively protected, the instability in basic-state activity is increased, the insertion process of ethylene monomers is accelerated and the high activity of the catalyst is further improved. Simultaneously, the space effect of a large-volume ligand can greatly reduce the transfer rate of an active chain to the monomers, so that a high molecular weight polymer can be obtained. In the presence of a cocatalyst, namely diethylaluminum chloride (DEAC), the catalyst has higher catalytic activity (which can achieve 106gPE/(mol Pd.h.Bar)) in catalysis of ethylene polymerization, and obtained polyethylene has higher degree of branching (which can achieve 123 branched chains/1000C). Therefore, the catalyst has great application value in olefin polymerization industry.