FI catalysts: new olefin polymerization catalysts for the creation of value-added polymers.

Abstract

This contribution reports the discovery and application of phenoxy-imine-based catalysts for olefin polymerization. Ligand-oriented catalyst design research has led to the discovery of remarkably active ethylene polymerization catalysts (FI Catalysts), which are based on electronically flexible phenoxy-imine chelate ligands combined with early transition metals. Upon activation with appropriate cocatalysts, FI Catalysts can exhibit unique polymerization catalysis (e.g., precise control of product molecular weights, highly isospecific and syndiospecific propylene polymerization, regio-irregular polymerization of higher alpha-olefins, highly controlled living polymerization of both ethylene and propylene at elevated temperatures, and precise control over polymer morphology) and thus provide extraordinary opportunities for the syntheses of value-added polymers with distinctive architectural characteristics. Many of the polymers that are available via the use of FI Catalysts were previously inaccessible through other means of polymerization. For example, FI Catalysts can form vinyl-terminated low molecular weight polyethylenes, ultra-high molecular weight amorphous ethylene-propylene copolymers and atactic polypropylenes, highly isotactic and syndiotactic polypropylenes with exceptionally high peak melting temperatures, well-defined and controlled multimodal polyethylenes, and high molecular weight regio-irregular poly(higher alpha-olefin)s. In addition, FI Catalysts combined with MgCl(2)-based compounds can produce polymers that exhibit desirable morphological features (e.g., very high bulk density polyethylenes and highly controlled particle-size polyethylenes) that are difficult to obtain with conventionally supported catalysts. In addition, FI Catalysts are capable of creating a large variety of living-polymerization-based polymers, including terminally functionalized polymers and block copolymers from ethylene, propylene, and higher alpha-olefins. Furthermore, some of the FI Catalysts can furnish living-polymerization-based polymers catalytically by combination with appropriate chain transfer agents. Therefore, the development of FI Catalysts has enabled some crucial advances in the fields of polymerization catalysis and polymer syntheses.