Synthesis And Application Exploration Of Polydentate Imine Ligand

With the development of social progress, polyethylene materials play an important role in daily life. So people demand more and more on the polyethylene material. Catalyst not only is one of key drivers for the synthesis of polyethylene into ethylene polymerization but also is the core technology of industrial development. In the recent years, metal complexes with polydentate imine ligands exhibit better catalytic properties in many reactions, especially in catalyzing ethylene polymerization. Based on the design of new ligands and their complexes, there has been synthesized several kinds of complexes and explored in aspect of catalyzing ethylene polymerization.This paper chooses 1,4-phthalaldehyde as main material to synthesize polydentate imine ligands with N-phenylethylenediamine, N-methylethylenediamine, o-phenylenediamine, m-phenylenediamine, 6-amino-2,4-dimethylpyridine, 2,6-dimethylaniline, 2,6-diisopropylaniline, 2-aminophenol, phenylhydrazine. Then according to the analysis method of ¹H NMR、¹³C NMR、IR, we try to analyze the structures of the formed ligand. We select high yield and relatively pure ligands L1, L2, L3, L5 to synthesize complexes. In this paper, we synthesize bimetal complexes 1a, 2a through the reaction of ligands L1, L2 with NiBr₂（DME） and complexes 3a, 3b, 5a, 5b through the reaction of ligands L3, L5 with NiBr₂（DME） and NiCl₂（DME） respectively. Finally ethylene polymerization experiment is carried out. Under ordinary pressure and EASC as cocatalyst, it investigates the influence of different reaction temperature and different Al/Ni on ethylene polymerization behavior, additionally we also carried out kinetic analysis. Under the reaction temperature is 30℃, and Al/Ni is 150, bimetal complexes 1a, 2a exhibit high activity, the products of catalyzing ethylene polymerization of two bimetal complexes are low carbon oligomer, no polymer. Under the reaction temperature is 40℃, and Al/Ni is 400, complexes 3a, 5a exhibit high activity, most of the products of catalyzing ethylene polymerization by the complexes are low carbon oligomer, mainly for 1-butylene and hexene, and a small amount of polymer. In addition, other conditions in the same situation, through comparison of the complexes of 3a and 3b, 5a and 5b found that different halogen atoms in catalyst has a large influence on the catalytic performance. Complexes containing NiBr₂ relative to NiCl₂ complexes have shorter induction period, but life is short.