Homogeneous vanadium-based catalysts for the Ziegler-Natta polymerization of alpha-olefins.
Although their activity is often inferior to that of other systems, the use of vanadium-based catalysts in homogeneous Ziegler-Natta polymerizations allows the preparation of high-molecular-weight polymers with narrow molecular-weight distributions, ethene/alpha-olefin copolymers with high alpha-olefin incorporation, and syndiotactic polypropene. The main reason for the low activity of these catalysts is their deactivation during catalysis by reduction of active vanadium species to low-valent, less active or inactive species. We here present an up-to-date review of this area with particular emphasis on the attempts to improve catalyst performance and stability by the use of additives or ancillary ligands.
Hagen
Henk
H
Debye Institute, Department of Metal-Mediated Synthesis, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Boersma
Jaap
J
van Koten
Gerard
G