Copolymerization of ethylene with linear α-olefins by 2-phosphinophenolate nickel catalysts
2009
Guo, Cun-Yue | Peulecke, Normen | Kindermann, Markus K. | Heinicke, Joachim W.
2-Dicyclohexyl- and 2-diphenylphosphinophenol, CCHH and PPHH, react with Ni(1,5-COD)₂ to form catalysts for polymerization of ethylene in or copolymerization with α-olefins. The more P-basic CCHH/Ni catalyst allows concentration-dependent incorporation of olefins to give copolymers with isolated side groups and higher molecular weights, whereas the PPHH/Ni catalyst undergoes mainly stabilizing interactions with the olefins and leads to ethylene oligomers with no or marginal olefin incorporation. Pressure-time plots of the batch reactions show that the ethylene conversion is usually slower by catalysis with CCHH/Ni than by PPHH/Ni. The microstructure of the copolymers was determined by ¹³C NMR spectra, the number of side groups per main chain was estimated by ¹H NMR analyses.
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