Synthesis And Catalytic Behaviors Of Iron,Cobalt And Nickel Catalysts For Ethylene Polymerization Bearing Benzhydrylnaphthyliminopyridines

This thesis was primarily dedicated to designing and synthesis of a series of pyridylimines or bis(imino)pyridines containing the benzhydryl-substituted naphthyl and their corresponding iron(II),cobalt(II)and nickel(II)complexes as catalysts.These metal catalysts were activated by Al-based co-catalysts and their catalytic performances were investigated in detail,including the ligand environment and various reaction conditions.Five chapters are included in this thesis as follows:In chapter 1,the detailed progress of transition metal complexes as olefin polymerization and/or oligomerization catalysts was reviewed,especially for late-transition metal catalysts including iron,cobalt and nickel.In chapter 2,a series of benzhydryl-substituted naphthylamine derivatives were designed and synthesized,and used to prepare the benzhydrylnaphthyliminopyridine organic ligand by the condensation reactions of the benzhydryl-substituted naphthylamines with 2-acetylpyridine.The organic compounds reacted with Ni Br₂(DME)[DME=Diethylene glucol dimethyl ether]or Ni Cl₂·6H₂O to synthesize their corresponding nickel complexes as catalysts.All the organic ligand and their nickel complexes were fully characterized.These nickel catalysts,when activated by Et₂Al Cl as co-catalyst,exhibited very high activities towards ethylene polymerization,producing highly branched polyethylenes with low molecular weight waxes and narrow polydispersity,suggestive of single-site active species.In chapter 3,a series of benzhydrylnaphthyliminopyridine ligand were prepared by the condensation reactions of the benzhydryl-substituted naphthylamines and picolinaldehyde and used to form their respective nickel complexes reacting with Ni Br₂(DME)or Ni Cl₂·6H₂O as catalysts.Upon activation with MAO or MMAO,these nickel catalysts could efficiently polymerize ethylene to produce high branched polyethylene waxes,the obtained polyethylenes waxes still possess very low molecular weight and narrow PDI.In chapter 4,a series of 8-(2-benzhydrylnaphthylimino)-5,6,7-trihydroquinoline organic ligand were synthesized by the condensation reactions of 5,6,7-trihydroquinolin-8-one and benzhydryl-substituted naphthylamine deriviatives and further reacted with Ni Br₂(DME)or Ni Cl₂·6H₂O to form corresponding nickel complexes as catalysts.Single crystal X-ray diffraction of the representative nickel complexes indicated a distorted octahedral geometry around nickel atom as the halo-bridged centro-symmetric dimers.When activated by either MAO or MMAO,all nickel catalysts performed high activities towards ethylene polymerization and produced low molecular weight and branched polyethylene waxes.Moreover,the GPC curves of the obtained polyethylenes showed tail peaks in the high molecular weight portion led to the wider PDI of these polyethylenes compared with the above two catalytic systems.In chapter 5,a series of 2-[1-(2,4-dibenzhydrylnaphthylimino)ethyl]-6-[1-(arylimino)ethyl]-pyridine ligand were prepared by the condensation reactions of 2,4-dibenzhydrylnaphthylamine and 2-acetyl-6-(arylimino)pyridine derivatives and used to prepare their corresponding iron and cobalt complexes with Fe Cl₂·4H₂O and anhydrous Co Cl₂ as catalysts.On activation with either MAO or MMAO,all these iron catalysts performed very high activities for ethylene polymerization and good thermal stability.In addition,the iron complexes could maintain high catalytic performances at higher reaction temperature;especially at 80°C as the industrial operating temperature,still showed high activity up to 8.57×10⁶ g(PE)·mol^-1(Fe)·h^-1.The catalytic systems have great potential for industrial application.This thesis was mainly prepared the benzhydrylnaphthyliminopyridine derivatives and their corresponding iron,cobalt and nickel complexes as catalysts,and then their catalytic performances and the properties of the polymers are investigated in detail.These results provided guidance for the design and development of novel late-transition metal complexes for olefin polymerization,thus promote the development of polyolefin industry.