Recent Advances in Phenoxy-Based Catalysts for Olefin Polymerization

Abstract

Olefiin polymerization behavior of phenoxy-based catalysts has been discussed. Phenoxy-based olefin polymerization catalysts are capable of showing high catalytic activities. Moreover, the phenoxy-based catalysts can display unique catalytic properties and thus have offered opportunities to make polyolefinic materials that are difficult or impossible to prepare using conventional catalysts. Therefore, the phenoxy-based catalysts have opened up a new dimension in the fields of olefin polymerization catalysis and polymer synthesis.

FI Catalyst for Polymerization of Olefin

“…In association with appropriate cocatalysts, many of these catalysts show ethylene polymerization activities that are superior or comparable to those seen with early group 4 transition metals metallocene catalysts. These post-metallocene catalysts can produce a wide array of distinctive polymers (e.g., hyper-branched PEs, ethylene-methyl acrylate copolymers, monodisperse poly(1-hexene)s, and block copolymers based onolefins), many of which were inaccessible using metallocene catalysts [3,[16][17][18][19][20][21][22][23][24].…”

“…Since the ligand structure has a central role in determining the activity as well as the stereospecifity of these types of catalysts, and as shown in Figure 2, flexible electronic nature of a ligand is a key requirement for achieving high activity, the research based on the ligand oriented catalyst design concept has resulted in the discovery of a number of highly active catalysts for the polymerization of ethylene, which include: phenoxy-imine ligand early transition metal complexes (FI catalysts), pyrrolide-imine ligand group 4 transition metal complexes (PI catalysts), indolide-imine ligand Ti complexes (II catalysts), phenoxy-imine ligand group 4 transition metal complexes (IF catalysts), phenoxy-ether ligand Ti complexes (FE catalysts), imine-pyridine ligand late transition metal complexes (IP catalysts), and tris(pyrazolyl) borate ligand Ta complexes (PB catalysts) (Figure 3) [20,[26][27][28][29][30]. In particular, bis(phenoxy-imine) group 4 metal catalysts, developed by Fujita [19][20][21] caused a new revolution in the field of catalytic olefin polymerization.…”

“…In particular, bis(phenoxy-imine) group 4 metal catalysts, developed by Fujita [19][20][21] caused a new revolution in the field of catalytic olefin polymerization. These complex catalysts exhibit unique characteristics for production of new polymers that are not prepared by conventional Ziegler-Natta catalysts, as well as by ordinary metallocene-type catalysts [16].…”

“…These complexes can typically combine with appropriate cocatalysts to form highly active catalysts for the polymerization of ethylene. Among these new complexes, bis(phenoxy-imine) early transition metal complexes (named FI Catalysts) are particularly versatile for olefin polymerization when activated (Figure 4) [20,21].…”

Novel titanium complexes bearing two chelating phenoxy‐imine ligands and their catalytic performance for ethylene polymerization

“…1,2 Among them, organometallic complexes containing Schiff bases have been widely used and investigated with a vast array of metals. They are attractive ligands because of their ease of preparation and modification of both steric and/or electronic effects.…”