Polymerization Of Conjugated Diolefin Catalyzed By Phosphonamine Rare Earth Complexes

The synthesis of new rare earth catalysts and the polymerization of conjugated diolefins have been an important direction.Phosphine amine rare earth catalyst has high coordination ability and more functional groups,so it is easy to control the structure of rare earth catalyst and realize the controlled polymerization of polyolefin.Conjugated diolefin is an important monomer of conjugated olefin.The conjugated diolefin polymer with controllable microstructure is also an important component of high performance synthetic rubber,and is widely used in medical,health,transportation,communication equipment and other fields.Poly?conjugated diolefins?with different microstructure can be obtained by the control of rare earth catalyst.In this paper,a series of N-P complexes were synthesized and applied to the polymerization of conjugated diolefins.The polymerization properties and polymerization rules of N-P complexes for isoprene and butadiene were investigated.1.A series of phosphine amine rare earth complexes were synthesized by using"N-P"type non-Cp ligands with nitrogen and phosphorus atoms at the same time:?C₆H₅NPPh₂?Y?CH₂C₆H₄NMe₂-o?₂?Cat.1?,?2,4,6-Me₃C₆H₂NPPh₂?Y?CH₂C₆H₄NMe₂-o?₂?Cat.2?,?2,6-ⁱPr₂C₆H₃NPPh₂?Y?CH₂C₆H₄NMe₂-o?₂?Cat.3?,?4-CH₃OC₆H₄NPPh₂?Y?CH₂C₆H₄NMe₂-o?₂?Cat.4?,?4-CF₃C₆H₄NPPh₂?Y?CH₂C₆H₄NMe₂-o??Cat.5?.2.Polymerization of isoprene catalyzed by?Cat.1?is with the 3,4-stereoselectivity33 mol%and the 1,4-stereoselectivity 67 mol%.?Cat.2?can catalyze isoprene polymerization with high 3,4-structure obtained.The content of polyisoprene in 3,4-structure was as high as60 mol%,while 1,4-structure in polyisoprene content was only 40 mol%.Polymerization of isoprene catalyzed by?Cat.3?is with the 3,4-stereoselectivity 98 mol%and the1,4-stereoselectivity 2 mol%.The polymerization of isoprene catalyzed by?Cat.4?gave the polyisoprene 1,4-structure polyisoprene content as high as 64 mol%and 3,4-structure polyisoprene content as only 36 mol%.The polymerization of isoprene catalyzed by?Cat.5?gave the polyisoprene with 1,4-structure polyisoprene content as high as 78 mol%and3,4-structure polyisoprene content only as 22 mol%.The polymerization rules of isoprene catalyzed by five catalysts are quite different.By changing the ligands,the isoprene polymerization was achieved from high 3,4-stereoselective polymerization to high 1,4-high stereoselective polymerization.Controllable stereostructure is obtained.3.Five complexes catalyzed homopolymerization of butadiene have been carried out to obtain high 1,4-selective polymerization of butadiene.The highest selectivity for butadiene is97 mol%,catalyzed by?Cat.5?.?Cat.3?and?Cat.2?take second place,which obtained1,4-stereoselectivity as 87 mol%,92 mol%.?Cat.4?gave the polybutadiene with 1,4-structure polybutadiene as 78 mol%and 3,4-structure polybutadiene content only as 22 mol%.Polymerization of butadiene catalyzed by?Cat.1?is with the 1,4-stereoselectivity 79 mol%and the 3,4-stereoselectivity 21 mol%.