Details

Autor(en) / Beteiligte

• Dötterl, Matthias
• Alt, Helmut G.

Titel

Silica Based Cocatalysts for Heterogeneous Olefin Dimerization and Ethene Polymerization Reactions with Nickel Complexes

Ist Teil von

• ChemCatChem, 2012-05, Vol.4 (5), p.660-667

Ort / Verlag

Weinheim: WILEY-VCH Verlag

Erscheinungsjahr

2012

Link zum Volltext

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• We have developed a new buffered silica‐based Lewis acid cocatalyst for olefin dimerization and polymerization reactions with nickel complexes. The Lewis acidities of EtAlCl2 and Et2AlCl‐modified silicas were adjusted by the addition of BiPh3 or N‐methylpyrrole buffers. The buffered heterogeneous cocatalysts were employed to activate nickel complexes for selective propene dimerization reactions to give dimers in 91 % yield. Buffer addition also reduced the rate of ligand ion from the catalytically active nickel center. In combination with a nickel diimine complex, ethene was polymerized to give 69 wt % polyethylene and 31 wt % oligomers. The polyethylene displayed a molecular mass of 154 kg mol−1 and a polydispersity index (PDI) of 3.26. The oligomers consisted of 93 % butenes, 46 % thereof being 1‐butene. Furthermore, triphenylbismuth‐buffered Lewis acidic chloroaluminate ionic liquids were coated on surface‐modified silica to yield a supported ionic liquid phase (SILP) system. Dimer selectivities of up to 94 % were obtained with the SILP system in nickel‐catalyzed propene dimerization reactions. The newly developed silica‐based cocatalysts provide promising new olefin dimerization systems suitable for fixed bed applications. Buffered cocatalysts get selective: In combination with triphenylbismuth or N‐methylpyrrole buffers, EtAlCl2 and Et2AlCl surface‐modified silicas are employed as heterogeneous cocatalysts of nickel complexes to catalyze selective olefin dimerization and polymerization reactions. Surface‐modified silica is coated with a BiPh3‐buffered chloroaluminate ionic liquid to give a supported ionic liquid phase (SILP) cocatalyst.