Study On Diolefin Polymerization By ?-Diimine Posttransition Metal System With Weak Interaction

Because imine structure has the advantages of simple synthesis and adjustable structure,it is the most widely used building unit in post transition metal complex catalysts.Many famous olefin polymerization catalysts are regulated on the basis of imine structure.How-ever,due to the C-H activation side reaction between ligand and metal center at high tem-perature,post transition metal complexes often show poor thermal stability in the polymeri-zation of olefins and diolefins.Based on this,this paper puts weak H···F interaction was incorporated into the ligand structure,and a series of novel ligands were prepared?-Nickel diimide catalyst.H in the ligand molecule F interaction can effectively control the rotation of N-aryl,so as to reduce the activation probability of C-H at high temperature,and then improve the thermal stability of the catalyst.Its catalytic polymerization behavior of butadi-ene and isoprene was deeply studied.The key research contents mainly include:Firstly,a series of asymmetry improved by axial and lateral resistance are synthesized?-Diimide Ni based catalyst and its catalytic homopolymerization of isoprene and copoly-merization with butadiene were studied in detail.Due to the joint influence of the increase of axial/lateral steric resistance and the non-covalent interaction of intramolecular H...F this series of catalysts show good heat resistance.At 110 ~oC,the series of catalysts still showed good catalytic behavior for the polymerization of isoprene,and the yield was more than 99%.The structure of the catalyst was characterized.The molecular weight and its distribution,microstructure and thermal properties of the polymer were characterized by GPC,FTIR,NMR and DSC.Secondly,butadiene polymerization was catalyzed by these catalysts and their catalytic behavior was studied.The results show that butadiene monomer can also be polymerized at high temperature.At the same time,this series of catalysts are also suitable for laurene mon-omer,and can achieve a catalytic yield of more than 96%.The effect of additional phospho-rus containing electron donors was also studied at high temperature.It was found that its catalytic activity depended on the type of electron donors,but the effect was good in most cases,and the monomer conversion could reach 90%.