Homopolymerization of methyl methacrylate by novel salicylaldiminate‐nickel/methylaluminoxane catalysts obtained by oxidative addition of the chelate ligand to a nickel(0) precursor

Abstract

Salicylaldimine ligands, such as 5-nitro-N(2,6-diisopropylphenyl)salicylaldimine, 3,5-dinitro-N(2,6-diisopropylphenyl)salicylaldimine, and 3-phenyl-N(2,6-diisopropylphenyl) salicylaldimine were checked in the oxidative addition to bis(1,5-cyclooctadiene)nickel(0) to prepare, after activation by methylaluminoxane (MAO), novel nickel-based catalytic systems active in the polymerization of methyl methacrylate. The catalytic behavior of the aforementioned systems, in terms of activity, molecular weight, and polydispersity of the resulting poly(methyl methacrylate) as well as its stereoregularity degree, was investigated as a function of the Al/Ni molar ratio, reaction temperature, and nature of the salicylaldimine ligand. The effect of ethylene atmosphere present during the preparation of the catalyst precursors was also investigated. The results are discussed and compared with those previously obtained by bis(salicylaldiminate)nickel(II)MAO catalytic systems. (C) 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1716-1724, 2003

Melt grafting of polymethyl methacrylate onto poly(ethylene‐co‐1‐octene) by reactive extrusion: Model compound approach

“…For instance, the formation of enolate species in methacrylate polymerizations is made so that the insertion of olefins will not occur due to the endothermicity of the insertion step 1. Recently, novel catalytic systems were claimed to be active in the copolymerization of ethylene with methylmethacrylate without preceding blocking of the ester group 4, 5. Nevertheless, the synthesis of such terpolymer (ethylene‐ co ‐octene‐ g ‐methylmethacrylate) can be considered through the in situ polymerization of methylmethacrylate in the presence of molten copolymer ethylene‐ co ‐octene during an extrusion operation by using free radical hydrogen abstractors like peroxides 6–8.…”

Highly active methyl methacrylate polymerization catalysts obtained from bis(3,5‐dinitro‐salicylaldiminate)nickel(II) complexes and methylaluminoxane

“…Very recently, new salicylaldiminate nickel(II) complexes ( II ) were prepared by the oxidative addition of mononitro‐ and dinitro‐substituted salicylaldimine ligands into bis(1,5‐cyclooctadiene)nickel(0) [Ni(cod) 2 ] according to Scheme 8, 9 . IIa and IIb were isolated and structurally characterized.…”

Structural characterization of nitro-substituted phenoxyiminato nickel complexes; inter-molecular π–π interactions in the solid states and effect of the electron drawing groups on catalytic activity

“…Carlini et al reported a Ziegler-Natta-type bis(nitro-substituted phenoxyiminato) nickel catalysts for homopolymerization of ethylene [19,22], styrene [23], norbornene [24] and methyl methacrylate (MMA) [20,21] with the methylalumoxane (MAO) or bis(1,5-cyclooctadiene)nickel(0) as cocatalysts. Herein, we report the introduction of nitro substitutes on the ortho and para-position of the phenol of the phenoxyiminato back-bone (Chart 1), as well as the synthesis and structural characterization of their nickel complexes.…”

“…Although the influence of electronic effect on catalytic activity of phenoxyiminato nickel(II) complexes [18], there have been a limited number of reports that describe the incorporation of electron drawing groups in the ligand ''back-bone" [19][20][21][22][23][24]. Carlini et al reported a Ziegler-Natta-type bis(nitro-substituted phenoxyiminato) nickel catalysts for homopolymerization of ethylene [19,22], styrene [23], norbornene [24] and methyl methacrylate (MMA) [20,21] with the methylalumoxane (MAO) or bis(1,5-cyclooctadiene)nickel(0) as cocatalysts.…”