A new Salan zirconium complex is synthesized and tested as a precatalyst for the polymerization of ethylene and higher a-olefins. Its catalytic behavior is compared to that of a previously reported and related Salen zirconium complex. Analysis of the produced polyolefins reveals that the two different catalytic systems produce polymers with the same microstructure: atactic polymers from propene versus highly isotactic polymers from higher a-olefins. The identification of the end groups indicates a prevailing primary regiochemistry of polyinsertion of the a-olefins for both Salan and Salen zirconium complexes. These observations strongly suggest the formation of very similar active species in both systems.
A comparative study on the polymerization of alpha-olefins catalyzed by Salen and Salan zirconium complexes
STRIANESE, MARIA;LAMBERTI, Marina;MAZZEO, Mina;PELLECCHIA, Claudio
2008-01-01
Abstract
A new Salan zirconium complex is synthesized and tested as a precatalyst for the polymerization of ethylene and higher a-olefins. Its catalytic behavior is compared to that of a previously reported and related Salen zirconium complex. Analysis of the produced polyolefins reveals that the two different catalytic systems produce polymers with the same microstructure: atactic polymers from propene versus highly isotactic polymers from higher a-olefins. The identification of the end groups indicates a prevailing primary regiochemistry of polyinsertion of the a-olefins for both Salan and Salen zirconium complexes. These observations strongly suggest the formation of very similar active species in both systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
