Creation of Value-added Olefin-based Materials by New Olefin Polymerization Catalysts Developed at Mitsui Chemicals

This contribution reports on the unique olefin polymerization catalysis of the new catalysts developed at Mitsui Chemicals and the associated synthesis of value-added olefin-based materials. Research based on a "ligand oriented catalyst design concept" has resulted in the discovery of a series of high-performance imine-based group 4 transition metal complex catalysts, represented by bis (phenoxy-imine) early transition metal catalysts (FI catalysts) and bis (pyrrolide-imine) group 4 transition metal catalysts (PI catalysts). These imine-based catalysts possess distinctive features that result in characteristic polymerization catalysis and unique polymer synthesis. The features include presence of structural isomers, fluxional character regarding the interconversion of the structural isomers, high electrophilicity of a catalytically active species, susceptibility to reduction at the imine functionality, and versatility vis-a-vis activator selection. With these fea-tures, the catalysts can form a wide variety of unique olefin-based materials, which include vinyl-terminated polyethylenes (PEs), well-defined and multimodal PEs, ultra-high molecular weight ethylene/a-olefin copolymers, highly isotactic and syndiotactic PPs (iPPs and sPPs), regio- and stereoirregular high molecular weight poly(higher a-olefin)s, and ultra-fine particle PEs. Additionally, we have found that these catalysts are capable of mediating highly controlled living olefin (co) polymerizations to produce a wide array of block copolymers from ethylene, propylene, higher a-olefins and norbornene. Moreover, we have successfully synthesized well-defined functionalized PEs, PE/polar polymer hybrid materials (from vinyl-terminated PEs) and functionalized ultra-fine particle PEs (from ultra-fine particle PEs). Many of the olefin-based materials described above were unavailable prior to our work.