Polymerization of olefins and polar monomers catalyzed by bis(imino)Ni(II)/dibutylmagnesium/alkylaluminium halide systems

Abstract

Abstract[Bis(N,N′‐dimesitylimino)acenaphthene]dibromonickel (1) when activated with diethylaluminium chloride (DEAC) is a very active catalyst for ethylene homopolymerization. The activity (AE) of 1/100 DEAC is twenty times greater than that of 1/100 MAO and of the same order of magnitude as 1/2000 MAO. In the case of homopolymerization of propylene the highest activity (AP) was obtained at a ratio of 25/15 for AlDEAC/Ni. Trialkylaluminium compounds were also found to act as cocatalysts for 1. The PE synthesized with four different cocatalysts was found by 13C NMR to have dissimilar branching distributions. 1/DEAC shows no activity for the polymerization of proximately substituted polar monomers. The introduction of dibutylmagnesium, (DBM) activates the 1/DEAC system to copolymerize ethylene and a number of proximately substituted polar monomers. Compared with the 1/MAO/monomer.AlR3 catalyst system the former is three times more active for copolymerization of 5‐hexene‐1‐ol or 10‐undecen‐1‐oic acid with ethylene. The activity of copolymerization is 1/24, 1/5 and 1/2 as active as homopolymerization, respectively, in the case of methyl vinyl ketone, vinyl acetate and ϵ‐caprolactam. In the case of tetrahydrofuran/ethylene, the 1/MAO catalyst produced copolymers using AlR3 pretreated THF whereas the 1/DEAC/DBM catalyst produces homopolyethylene only. No polymerization occurred with an acrylonitrile/ethylene mixture in the presence of 1/DBM/DEAC catalyst.© 2002 Society of Chemical Industry