Description:
Project ID: D2009-89
Background
Polymerization reactions are used in industry to make widely used products, such as polyolefins. There has been an interest in improving control over polymer tacticity and co-polymerization, leading to the development of Constrained Geometry Catalysts (CGCs). The CGCs form complexes with a pi-bonded moiety bridged to a donor group on a shared metal center. The angle formed results in a constrained geometry and an active catalyst for polymerization. CGCs are typically dianionic and made with group 3 and 4 metals, with a strong focus on titanium and zirconium. Although these metals have been found to be active, complexes incorporating group 5 and 6 metals with trianionic ligands are desirable for greater control over polymer properties.
Invention Description
Researchers from the University of Toledo have created a catalyst system for producing CGCs that can incorporate group 4-6 metals. Trianionic ligand precursors are utilized to make homogenous and heterogeneous CGCs that act as single-site molecular compounds. The technology results in the formation of a six-membered chelate ring and a unique coordination environment in comparison to other CGCs.
Applications
• Polyolefins, polyethers, fine chemicals, and pharmaceutical intermediates
• Metathesis reactions
• Hydroamination of alkenes
• Oligomerization
• Polymerization of alkenes, epoxides, cyclic ethers, lactones, and other monomers
Advantages
• Precise control over polymer properties, such as tacticity and molecular weight
• Tunable to achieve desired activity and selectivity of catalyst
• Compatible with group 4-6 metals
IP Status: Issued U.S. Utility Patent 8,524,846
Publication: R. T. Rondo 2010. Development of Constrained Geometry Complexes of Group 4 and 5 Metals.