Morphology control of clay-mineral particles as supports for metallocene catalysts in propylene polymerization

Spray dry granulation of clay minerals was studied to obtain clay mineral base support material for metallocene supported olefin polymerization catalysts. The morphology of the granules was strongly influenced by the nature of the clay mineral itself. Because of swelling characteristics of montmorillonite, its water dispersion was highly viscous even in the low slurry concentration (< 4 wt %). Therefore, it was very difficult to control the granule characteristics such as size, shape, and inside structure by the spray dry with the clay mineral slurry. Then we examined some methods in order to change the clay mineral surface properties for getting less viscous dispersion. It was found that the milling of montmorillonite increased the amount of surface OH groups. This surface characteristic change should promote the interaction between the edges and basal planes of the primary particles of milled montmorillonite, resulting in the lowering the slurry viscosity. The milling is effective for overcoming difficulty in use of high concentration montmorillonite slurry in spray dry granulation which is indispensable for producing granules in the wide range of size (10–50 μm). The spray-dried montmorillonite granules are useful as a "Support-Activator" for an olefin polymerization catalyst combined with metallocenes

Nickel-Catalyzed Propylene/Polar Monomer Copolymerization

Nickel complexes bearing bidentate alkylphophine–phenolate ligands were synthesized and applied to the polymerization of propylene and the copolymerization of propylene and polar monomers. Therein, the use of bulky alkyl substituents on the phosphorus atom was crucial for the formation of highly regioregular polypropylenes. Theoretical calculations suggested that the 1,2-insertion of propylene is favored over the 2,1-insertion in these nickel-catalyzed (co)­polymerization reactions. The substituent at the <i>ortho</i> position relative to the oxido group greatly influences the polymerization activity, the molecular weight, and stereoregularity of the polypropylenes. This method delivers moderately isotactic ([<i>mm</i>] ≤ 68%) crystalline polypropylenes. The present system represents the first example for a nickel-catalyzed regiocontrolled copolymerization of propylene and polar monomers such as but-3-en-1-ol, but-3-en-1-yl acetate, and <i>tert</i>-butyl allylcarbamate

Nickel-Catalyzed Propylene/Polar Monomer Copolymerization

Nickel complexes bearing bidentate alkylphophine–phenolate ligands were synthesized and applied to the polymerization of propylene and the copolymerization of propylene and polar monomers. Therein, the use of bulky alkyl substituents on the phosphorus atom was crucial for the formation of highly regioregular polypropylenes. Theoretical calculations suggested that the 1,2-insertion of propylene is favored over the 2,1-insertion in these nickel-catalyzed (co)­polymerization reactions. The substituent at the <i>ortho</i> position relative to the oxido group greatly influences the polymerization activity, the molecular weight, and stereoregularity of the polypropylenes. This method delivers moderately isotactic ([<i>mm</i>] ≤ 68%) crystalline polypropylenes. The present system represents the first example for a nickel-catalyzed regiocontrolled copolymerization of propylene and polar monomers such as but-3-en-1-ol, but-3-en-1-yl acetate, and <i>tert</i>-butyl allylcarbamate

Nickel-Catalyzed Propylene/Polar Monomer Copolymerization

Nickel complexes bearing bidentate alkylphophine–phenolate ligands were synthesized and applied to the polymerization of propylene and the copolymerization of propylene and polar monomers. Therein, the use of bulky alkyl substituents on the phosphorus atom was crucial for the formation of highly regioregular polypropylenes. Theoretical calculations suggested that the 1,2-insertion of propylene is favored over the 2,1-insertion in these nickel-catalyzed (co)­polymerization reactions. The substituent at the <i>ortho</i> position relative to the oxido group greatly influences the polymerization activity, the molecular weight, and stereoregularity of the polypropylenes. This method delivers moderately isotactic ([<i>mm</i>] ≤ 68%) crystalline polypropylenes. The present system represents the first example for a nickel-catalyzed regiocontrolled copolymerization of propylene and polar monomers such as but-3-en-1-ol, but-3-en-1-yl acetate, and <i>tert</i>-butyl allylcarbamate

Methylene-Bridged Bisphosphine Monoxide Ligands for Palladium-Catalyzed Copolymerization of Ethylene and Polar Monomers

A series of palladium complexes bearing a bisphosphine monoxide with a methylene linker, that is, [κ²-<i>P</i>,<i>O</i>-(R¹₂P)­CH₂P­(O)­R²₂]­PdMe­(2,6-lutidine)]­[BAr^F₄] (Pd/BPMO), were synthesized and evaluated as catalysts for the homopolymerization of ethylene and the copolymerization of ethylene and polar monomers. X-ray crystallographic analyses revealed that these Pd/BPMO complexes exhibit significantly narrower bite angles and longer Pd–O bonds than Pd/BPMO complexes bearing a phenylene linker, while maintaining almost constant Pd–P bond lengths. Among the complexes synthesized, menthyl-substituted complex <b>3f</b> (R¹ = (1<i>R</i>,2<i>S</i>,5<i>R</i>)-2-isopropyl-5-methylcyclohexan-1-yl; R² = Me) showed the best catalytic performance in the homo- and copolymerization in terms of molecular weight and polymerization activity. Meanwhile, complex <b>3e</b> (R¹ = <i>t</i>-Bu; R² = Me) exhibited a markedly higher incorporation of comonomers in the copolymerization of ethylene and allyl acetate (≤12.0 mol %) or methyl methacrylate (≤0.6 mol %). The catalytic system represents one of the first examples of late-transition-metal complexes bearing an alkylene-bridged bidentate ligand that afford high-molecular-weight copolymers from the copolymerization of ethylene and polar monomers