Synthesis Of Bulky α-diimine Catalyst And Its Catalytic Olefin Polymerization

Throughout the development of polyolefins,catalysts have always played an extremely important role,Compared with traditional Ziegler-Natta catalysts and metallocene catalysts,late transition metal catalysts have attracted much attention in recent years due to their unique properties.This type of catalyst can catalyze the formation of different properties by changing the ligand structure.Polymer;In addition,it can also catalyze the copolymerization of olefins and polar monomers.However,its poor heat resistance is a major factor restricting its development.Introducing large sterically hindered substituents and changing the ligand framework are two common solutions to improve catalyst stability.In this paper,eight kinds of catalyst ligands with large hindered substituents were prepared.Among them,two kinds ofα-diimine ligands with symmetric structure and two asymmetric structures were synthesized with acenaphthenquinone as the skeleton;A ketone as the skeleton,anα-diimine ligand with an asymmetric structure was synthesized;with 9,10-dihydro-9,10-ethylanthracene-11,12-dione as the skeleton,aΑ-diimine ligand with symmetric structure;using 2,6-diacetylpyridine as the skeleton,a pyridine diimine ligand with a symmetric structure and an asymmetric structure was synthesized;A variety of synthesis schemes were developed and characterized by a variety of tests.We put N,N-bis（2,6-diisopropyl-4-bis（4-（hydroxymethyl）phenyl）methyl-phenyl）acenaphthylene-1,2-diimine（L1）It is coordinated with Ni（DME）Br₂to form Cat-Ni as a catalyst,and 2,6-bis[1-（2,6-diisopropyl-4-bis（4-（hydroxymethyl）phenyl）methyl-Phenylimino）ethyl]-pyridine（L7）and Fe Cl₂?4H₂O are coordinated to form Cat-Fe as a catalyst,which is characterized by infrared spectroscopy;the catalytic activity of Cat-Ni for ethylene polymerization at different polymerization temperatures is discussed.It shows that the activity is the highest at 70℃,reaching5.97×10⁶g/（mol×h）,and at 90℃,it shows higher catalytic activity,reaching4.15×10⁶g/（mol×h）,indicating that Cat-Ni has good The heat resistance of Cat-Fe has been discussed at different polymerization temperatures and different molar ratios of aluminum to iron.The study shows that the activity is the highest at 30℃,reaching 1.17×10⁶g/（mol×h）,when aluminum When the iron molar ratio drops to800,the activity can still reach 1.04×10⁶g/（mol×h）at 70℃,indicating that Cat-Fe has good stability.