Applications Of Phosphine Sulfonate Palladium And Nickel Catalysts In Olefin And Polar Monomer Copolymerization Reactions

Since Ziegler and Natta discovered olefin polymerization catalysts,transition metal-catalyzed olefin polymerization has achieved great success both in industry and academia.One of the major discoveries in the field of copolymerization of olefin with polar monomers is the phosphophenylsulfonate catalysts reported by Drent et al.in the 1990s.Since then,a large number of phosphine sulfonate-based palladium and nickel catalysts(especially palladium catalysts)have been widely used in the polymerization of ethylene and the copolymerization of ethylene with various polar monomers.After many years of research,there have been a variety of ways to adjust the ligands.Researchers have developed various types of functional ligands for the optimization and regulation of the catalysts.Most of the researches focused on the substituents on the phosphorous atom.However,tt is becoming increasingly difficult to obtain new and efficient palladium catalyst by changing the phosphorous substituents.In this thesis,we try to develop new ligand "platform".By changing the skeleton of the phosphine sulfonate ligands,we wish to make a breakthrough to overcome the common disadvantages of classic catalysts(such as low molecular weight,low activity,low polar monomer incorporation),and apply the new catalysts in the copolymerization of ethylene with polar monomers.1.First,we synthesized and characterized a novel phosphine sulfonate ligand based on naphthalene backbone.The corresponding phosphine sulfonate palladium and nickel catalysts were prepared from the reactions of the ligands with appropriate metal precursors.Under different conditions,the ethylene polymerization and ethylene and polar monomer copolymerization were studied.Compared with the classic PO catalysts,the change in the skeleton caused great changes in the nature of the catalysts,such as higher polymerization activities(up to 10 times),higher polymermolecular weights,higher melting temperatures,greater stability,and greater water tolerance.At the same time,the new naphthalene based catalysts are great in the copolymerization of ethylene with methyl acrylate,and the comonomer incorporation ratio can be as high as 40%.2.After discovery of these new and high performance naphthalene based catalysts,we continue to study the potentials of such PO catalyst system.By changing the connectivity of the phospohine and the sulfonate groups,the catalytic properties could be modified.Based on this idea,we prepared and characterized a series of catalysts,and found that they showed great properties in ethylene polymerization and copolymerization with polar monomers.This study provides a new research direction to improve the properties of various catalysts.3.In the naphthalene system,an oxygene containing functional group was designed.A series of metal catalysts were prepared by introducing the-OM(M is Li,Na,K)groups.In olefin polymerization and copolymerization,the properties of the metal catalysts could be influenced by different alkali metals and the addition of different crown ethers.4.Other attempts were made in the synthesis and characterization of modified phosphine sulfonate catalysts.