Synthesis Of Non-bridged Halftitanocenes Containing Arylsufide Ligands And Their Application For Ethylene/1-Octene Copolymerization

Polymeric materials are currently indispensable to our society which improves our quality of life.Polyolefin catalysts are the soul of the polyolefin industry,the development of which has mainly undergone several stages of Ziegler-Natta catalysts,metallocene catalysts,constrained-geometry catalysts and non-metallocene catalysts.Among them,metallocene catalyst occupies a leading position.At present,a lot of research work is devoted to the synthesis,characterization and catalytic performance of new metallocene catalysts.This thesis is based on the study of non-bridged half-titanocenes containing arylsufide ligands,and is divided into the following two parts:Synthesize a series of half-titanocenes containing arylsulfide ligands Cp Ti(S-2,6-Cl2C6H3)Cl2,Cp^*Ti(S-2,6-Cl2C6H3)Cl2,Cp^*Ti(S-2,6-Me2C6H3)Cl2,Ind Ti(S-2,6-Cl2C6H3)Cl2,Cp^*Ti(S-2,6-Cl2C6H3)Me2,and they were characterized by nuclear magnetic resonance(NMR)and X-ray single crystal diffraction(XRD).X-ray single crystal diffraction analysis of Cp Ti(S-2,6-Cl2C6H3)Cl2 and Cp^*Ti(S-2,6-Cl2C6H3)Cl2shows that a twisted tetrahedral structure is formed in the center of the titanium metal and its surroundings.Investigate the influence of polymerization temperature,monomer fraction,co-catalyst selection and ligand structure on the performance of the synthesized catalyst in olefin polymerization.The polymer was characterized by DSC,high temperature GPC and high temperature NMR.Under the action of cocatalyst B(C₆F₅)₃,thie type of complex can catalyze the copolymerization of ethylene and 1-octene with higher activity,the structure of the ligand and the polymerization conditions have a significant impact on the activity of the catalyst and the properties of the polymer.The results show that under the conditions of 30°C and 5 atm,these complexes can catalyze the copolymerization of ethylene and 1-octene in high activity,and polymers with high molecular weight and high1-octene content can be obtained.Among them,Cp^*Ti(S-2,6-Cl₂C₆H₃)Cl₂ shows the highest catalytic activity,and Cp Ti(S-2,6-Cl₂C₆H₃)Cl₂ shows the highest octene insertion rate.In addition,the modification of polymerization temperature,Cp group and anionic ligand will also affect the catalytic performance of the complex obviously.