Study On Olefin Polymerization Catalyzed By Bulky Iminephosphine Nickel-palladium And Phosphonosulfonate

Since the polymer materials was published,because of its superior mechanical properties,good chemical stability and low price,it is favored by industry and the public,and polyethylene is the most widely used material in polymer materials and has a pivotal position in national life.The synthesis of polyolefins is inseparable from the application of catalysts,from the beginning of Ziegler-Natta catalysts to metallocene catalysts,from former transition metal catalysts to late transition metal catalysts,the design and preparation of new catalysts have always been the core content of research on polyolefins,which requires not only high catalytic activity and thermal stability,but also obtain polymer with high molecular weight and narrow molecular weight distribution,and even possible to adjust the isotacticity of the polymer and the insertion of polar monomers by changing the ligands on the catalyst framework,thereby expanding the application of polyolefins in more fields and increasing commercial value.Late transition metal catalysts are increasingly concerned by researchers due to their excellent plasticity and low oxygen affinity.In this paper,a series of Ni/Pd catalysts containing large steric substituents based on the late transition metal catalyst,and confirmed their structures by ¹H,¹³C,FT-IR and MS.Then catalyzed olefin polymerization,the physical properties and microstructure of the polymer were controlled by adjusting and optimizing the substituents on the catalyst ligand framework,the polymerization conditions and the incorporation of copolymerized polar monomers.Research contents 1:（1）Synthesis and Confirmation of 2,6-Diphenylmethylimidine Phosphine Ni and Pd Catalysts.Firstly,2-diphenylphosphine benzaldehyde and4-r-2,6-diphenylmethylaniline（R=Me and F）were condensed with formic acid as catalyst to prepare iminophosphine ligands L1 and L2,then the ligands L1 and L2 were reacted with equal molar Ni Br₂（DME）or（Me CN）₂Pd Cl₂in anhydrous and anaerobic dichloromethane,and the large volume imine phosphine Ni and Pd complexes containing 2,6-diphenyl methyl were obtained efficiently,the synthesized ligands and complexes were characterized and confirmed by hydrogen spectrum,carbon spectrum,phosphorus spectrum,infrared spectrum and elemental analysis.（2）Applied research.These Ni pre-catalysts activated by Et₂Al Cl have excellent thermal stability and catalytic performance,the optimal polymerization activity of 1.90×10⁵g PE（mol Ni）^-1h^-1,up to 126℃melting temperature and high molecular weight polyethylene can be obtained when the molar ratio of the cocatalyst[Al]to the imine phosphine Ni complex is 500 and the temperature is 50℃.At the same time,Pd catalyst conducted ethylene oligomerization at high temperature in high yield to produce C10-C24 oligomers.The research found that the prepared iminophosphorous Ni and Pd catalysts have good thermal stability,and the catalytic activity and molecular weight of the polymer are improved by modification of the ligand N-aryl substituents.Research contents 2:（1）Synthesis of P-benzenesulfonic acid Pd catalyst.Firstly,a catalyst containing large volume P substituents at the benzyl position of benzenesulfonic acid by using 2,5-dimethylbenzenesulfonic acid as raw material.Then the ligands and their complexes were characterized and confirmed by hydrogen spectroscopy,carbon spectroscopy,phosphorus spectroscopy and elemental analysis techniques.（2）Applied research.Using the synthesized catalyst for ethylene polymerization,the study found that the synthesized catalyst contains a biaryl substituent palladium catalyst with good stability and catalytic activity(up to 2.3×10⁵g PE（mol PD）^-1h^-1)and narrow molecular weight distribution.In the process of copolymerization with polar monomers,the palladium catalyst containing biaryl substituents also has good catalytic activity and high molecular weight.