Toward Single-Site, Immobilized Molecular Catalysts: Site-Isolated Ti Ethylene Polymerization Catalysts Supported on Porous Silica

摘要

Soluble transition metal complexes are nearly ideal catalysts because of the versatile chemical properties that can be incorporated into them - the symmetry, sterics, and electronics of the active center can all be controlled using molecular design principles. However, industrial implementation of catalytic technologies often requires a solid catalyst. Thus, transition metal complex catalysts have been immobilized on solid supports for decades. Usually, the performance of the supported catalysts is significantly inferior as compared to the homogeneous analogues. This is due to many factors, with a primary cause being the formation of multiple types of ill-defined metal species on the solid support. For example, single-site transition metal complexes such as Group 4 metallocenes and related complexes have been developed as revolutionary new olefin polymerization catalysts.