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Silica Based Cocatalysts for Heterogeneous Olefin Dimerization and Ethene Polymerization Reactions with Nickel Complexes
Author(s) -
Dötterl Matthias,
Alt Helmut G.
Publication year - 2012
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201100484
Subject(s) - chemistry , nickel , lewis acids and bases , polymerization , polymer chemistry , propene , olefin fiber , ligand (biochemistry) , polyethylene , catalysis , yield (engineering) , organic chemistry , polymer , materials science , biochemistry , receptor , metallurgy
We have developed a new buffered silica‐based Lewis acid cocatalyst for olefin dimerization and polymerization reactions with nickel complexes. The Lewis acidities of EtAlCl 2 and Et 2 AlCl‐modified silicas were adjusted by the addition of BiPh 3 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 abstraction 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.