Polymerization Of Isoprene Catalyzed By PN~3 Cobalt Catalyst

A PN³ type ligand was synthesized and a series of PN³ cobalt catalysts were synthesized with cobalt compounds.Their effects on the?co?polymerization of isoprene,butadiene,myrcene and functional monomers were investigated.1.Designed and synthesized a series of new PN³ ligands and corresponding cobalt complexes.The complex was characterized by IR and elemental analysis,and part of the catalyst structure was characterized by single crystal diffraction.The complexes adopt a twisted octahedron centered on metal ions and a twisted triangular double cone configuration.The cis-1,4-alt-3,4 structure of polyisoprene was synthesized by Co2 under the activation of MMAO,and the microstructure was experimentally shown to be independent of the amount of cocatalyst.Co1 and Co3 exhibit a higher cis-1,4 selectivity.The molecular weight and distribution were well controlled at 0,30 and 50 ^oC,and the polymerization rate?kobs?increased in this order;therefore,the activation energy of 27-31kJ/mol was calculated.The catalyst system Co4-Co6/AlEt₂Cl mainly has a cis-1,4 selectivity of86.6-93.4%and a 3,4 selectivity of 6.6-13.4%.Both the structure of the ligand and the proportion of cocatalyst affect the microstructure.2.Under the activation of AlEt₂Cl,all cobalt complexes can be polymerization of myrcene,isoprene and butadiene,and have high cis-1,4 selectivity?66.1%-98.4%?.The steric hindrance of the catalyst,the amount of cocatalyst feed and the temperature change,have an effect on the polymer yield,but the microstructure of the polymer is negligible.A novel bioderived lauryl poly?myrcene-isoprene?with controlled incorporation of myrcene can be adjusted by monomer feed without significantly affecting the microstructure of each segment.3.Designed and synthesized a series of new cobalt complexes.A series of functional monomers were synthesized by using bio-sourced monomer as a template.Copolymerization of isoprene with functional monomers is catalyzed by a cobalt catalyst.Under the activation of AlEt₂Cl,the cobalt complex exhibits high catalytic activity for the copolymerization of myrcene and isoprene,and has a high cis-1,4 selectivity?80.0%-87.3%?.It is also highly active for the copolymerization of isoprene with functional monomers.