Synthesis Of Phenylthiophenol Titanocene Catalyst And Its Application In The Synthesis Of Functionalized Polyolefin

Polyolefin is widely used in various fields,but its chemical inertness makes it limited in many applications.The preparation of functionalized polyolefin can improve the properties of polyolefin materials and expand its application field.The polyolefin with reactive groups is synthesized by the transition metal coordination insertion,and the functional polyolefin can be prepared by the functionalization.In this paper,three different metal complexes were designed and synthesized,and the structures of the metal complexes and related ligands were characterized by nuclear magnetic resonance,elemental analysis and XRD-single crystal diffraction.In addition,the catalytic performance was studied,and the active polyolefin intermediate with hanging external double bond was successfully synthesized,and the functional polyethylene was prepared.The main work of this paper is summarized as follows:2,6-diisopropyl phenylthiophenol ligand and its corresponding titanocene complexes were designed and synthesized.The titanium monocene complexes are Cp*TiCl₂（S-2,6-ⁱPr₂-C₆H₃）（Ti1）,CpTiCl₂（S-2,6-ⁱPr₂-C₆H₃）（Ti2）and IndTiCl₂（S-2,6-ⁱPr₂-C₆H₃）（Ti3）.The structure of the metal complexes was characterized by nuclear magnetic resonance,elemental analysis and XRD single crystal diffraction.The application of three metal complexes in ethylene polymerization was systematically studied.Under the same conditions,the catalytic properties of Ti3>Ti1>Ti2 were obtained and the Ti3 showed the highest catalytic activity of 3.78×10⁶g（PE）mol^-1（Ti）.h^-1.Based on the study of ethylene homopolymerization,the application of Ti1,Ti2 and Ti3 in the copolymerization of ethylene and 1,7-octydiene was studied.Active polyolefin intermediates with hanging external double bond units（VHX）were successfully synthesized by inserting 1,7-octtadiene 1,2-addition into the ethylene main chain,and the VHX insertion rate in the synthesized copolymer could be effectively regulated.The insertion rate of VHX unit in Ti3 copolymer was 49.76%.During the copolymerization of Ti1 and Ti3,no cross-linked polymers were formed,and 12.3%of the copolymers catalyzed by Ti2 were cross-linked.The steric hindrance of the complex has an effect on the non-conjugated diene insertion.Too large hindrance is not conducive to insertion,and too small hindrance will lead to the synthesis of crosslinked copolymers.Finally,functional polyethylene copolymer was prepared by active polyolefin intermediate.