Copolymerization of Ethylene and Acrylates by Nickel Catalysts

Copolymerization of Ethylene and Polar Monomers by Using Ni/IzQO Catalysts

“…[2,6] Hence,the replacement of palladium with the more abundant and less expensive nickel has been examined, leading to the development of nickel catalysts, [6] for example, 1-Ni, [1,[7][8][9] 2-Ni, [10,11] 3, [12,13] 4, [14][15][16][17] 5, [18] and 6-Ni [19] (Figure 1). [2e,20, 21] Compared with palladium-based catalysts,t he corresponding nickel-based catalysts suffer from several critical drawbacks,s uch as 1) poor temperature tolerance [22] ,2 )low molecular weight of the obtained (co)polymers,and 3) heavier suppression by polar monomers,w hich undermine their economic value.B ecause olefin polymerization is ah ighly exothermic reaction, processes requiring low temperatures are difficult to control and their use of thermal drain is less efficient.…”

Coordination Copolymerization of Polar Vinyl Monomers H2CCHX

“…(1)] on the growing chain during polymerization, highly branched amorphous polyethylenes with the acrylate repeat units located predominantly at the ends of branches are obtained (see also Scheme 2). [9] However, in contrast to acrylates, other common comonomers such as VA, AN, and vinyl chloride (VC) could not be copolymerized by these cationic complexes. Very recently, significant advances have been reported with neutral Pd II catalysts, which are highlighted herein.…”

“…Remarkably, a linear ethylene-MA copolymer is obtained (Scheme 2; in the homopolymerization of ethylene, linear polyethylene is formed). [9] Theoretical studies suggest that the absence of "chain walking" [Eq. (1)] is due to an increased barrier to bhydride elimination relative to the cationic Pd diimine systems.…”

Titanium (IV) and Nickel (II) Catalysts Based on Anilinotropone Ligands

“…Neutral Ni catalysts modeled after -diimine complexes, containing bulky ortho-disubstituted arylimine functionality, have been reported. Catalysts based on salicylaldimines (Figure 8), have been described by both the DuPont [57] and the Grubbs groups [58,59]. The most active systems contain either electron-withdrawing nitro substituents in the aromatic ring [57] or bulky substituents at C-3, with a 9-anthracenyl group being most effective [58,59].…”

“…Catalysts based on salicylaldimines (Figure 8), have been described by both the DuPont [57] and the Grubbs groups [58,59]. The most active systems contain either electron-withdrawing nitro substituents in the aromatic ring [57] or bulky substituents at C-3, with a 9-anthracenyl group being most effective [58,59]. In the latter case, activities of 1.3 ×10 5 kg PE mol Ni -1 h -1 and lifetimes in excess of 6 h have been observed at 45-50 °C [58].…”