Immobilization of η 5 -cyclopentadienyltris(dimethylamido)zirconium polymerization catalysts on a chlorosilane- and HMDS-modified mesoporous silica surface: a new concept for supporting metallocene amides towards heterogeneous single-site-catalysts

Autor: Frédéric Lefebvre, Gerd T. Puchta, Horst Schneider, Wolfgang A. Herrmann, Guillaume Saggio, Gabriele Raudaschl-Sieber, Franz A. R. Kaul, Dimitrios Mihalios, Jean-Marie Basset
Rok vydání: 2001
Předmět:
Zdroj: Journal of Molecular Catalysis A: Chemical. 170:127-141
ISSN: 1381-1169
DOI: 10.1016/s1381-1169(01)00051-6
Popis: The modification of a mesoporous silica surface with Si(Ind)(CH3)2Cl and the immobilization of CpZr(NMe2)3 on this surface was studied via IR-spectroscopy. To reduce side reactions, the indenyl-modified silica was reacted with hexamethyldisilazane (HMDS) under IR-control before the CpZr(NMe2)3-immobilization. The role of the hydroxyl group protection with HMDS is discussed. The surface modifications have been repeated via Schlenk technique at the same conditions and the surface modifications were studied with 13 C CP MAS–NMR, 1 H MAS–NMR, elemental-, SEM- and BET-analysis. The surface species of the resulting catalysts are discussed. The precatalysts have been treated with methylaluminoxane (MAO) (Al:Zr (mol:mol)=500:1) and the resulting Zr contents (leaching-effect) are discussed. All catalysts have been tested in ethylene and propylene polymerization.
Databáze: OpenAIRE
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