Details

Autor(en) / Beteiligte

• Kilpatrick, Alexander F. R
• Rees, Nicholas H
• Turner, Zoë R
• Buffet, Jean-Charles
• O'Hare, Dermot

Titel

Physicochemical surface-structure studies of highly active zirconocene polymerisation catalysts on solid polymethylaluminoxane activating supports

Ist Teil von

• Materials chemistry frontiers, 2020-11, Vol.4 (11), p.3226-3233

Ort / Verlag

London: Royal Society of Chemistry

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Physicochemical surface-structure studies of highly active slurry-phase ethylene polymerisation catalysts has been performed. Zirconocene complexes immobilised on solid polymethylaluminoxane (sMAO) (sMAO-Cp 2 ZrX 2 ), have been investigated using SEM-EDX, diffuse reflectance FT-IR (DRIFT) and high field (21.1 T) solid state NMR (ssNMR) spectroscopy. The data suggest a common surface-bound cationic methylzirconocene is the catalytically active species. 91 Zr solid sate NMR spectra of sMAO-Cp 2 ZrCl 2 and sMAO-Cp 2 ZrMe 2 are consistent with a common surface-bound Zr environment. However, variation of the σ-donor (X) groups on the metallocene precatalyst leads to significant differences in polymerisation activity. We report evidence for X group transfer from the precatalyst complex onto the surface of the aluminoxane support, which in the case of X = C 6 F 5 , results in a 38% increase in activity. Static 91 Zr ssNMR, SEM-EDX, and DRIFT spectroscopy indicate that a common zirconium species, [Cp R 2 ZrMe] + , is present in all sMAO supported catalyst systems.