نتایج جستجو برای: dual site ethylene polymerization catalysts
تعداد نتایج: 590720 فیلتر نتایج به سال:
A series of titanium and zirconium complexes with ligands based on di-isopropyl phosphorus-phenylamine and their derivatives were synthesized and characterized. These catalysts were utilized to catalyze the copolymerization of ethylene with N-acetyl-O-(dec-9-enyl)-L-tyrosine ethyl ester with high catalytic activity of 6.63 × 104 g P (mol Ti)−1 h−1 after activation by methylaluminoxane (MAO). Th...
A series of new, highly fluorinated neutral (kappa(2)-N,O) chelated Ni(II) binuclear complexes based on salicylaldimines bridged in p-position of the N-aryl group were prepared. The complexes are single-component catalyst precursors for ethylene polymerization in supercritical carbon dioxide and toluene. Solubility of the catalyst precursors in supercritical carbon dioxide is effected by a larg...
Soluble polymers have been used as supports for reagent/catalyst immobilization and synthesis. Two polymers are commonly used in this context, linear polystyrene and poly(ethylene glycol). The complementary solubility properties of these polymers allow access to a wide range of chemistries. Parallel and combinatorial libraries of small molecules have been prepared using these polymers, and reag...
Dinickel complexes supported by terphenyl ligands appended with phenoxy and imine donors were synthesized. Full substitution of the central arene blocks rotation around the aryl-aryl bond and allows for the isolation of atropisomers. The reported complexes perform ethylene polymerization in the presence of amines. The inhibiting effect of polar additives is up to 250 times lower for the syn iso...
Abstract Recent progress in macromolecular reaction engineering has enabled the synthesis of sequence‐controlled polymers. The advent olefin block copolymers (OBCs) via chain shuttling polymerization ethylene with α‐olefins opened new horizons for polyolefins having a dual character thermoplastics and elastomers. Nevertheless, use two catalysts different comonomer selectivities agent, dragging ...
Nickel(II) complexes have attracted much attention as a new generation of olefin catalysts since the α-diiminonickel complex was discovered as a highly efficient procatalyst for ethylene polymerization. A series of novel 4-arylimino-1,2,3-trihydroacridylnickel(II) dihalide complexes was synthesized in a one-pot reaction of 2,3-dihydroacridine-4-one and different anilines with nickel(II) chlorid...
A new heterogeneous catalyst for CO(2) activation was identified in the Cr(II)/SiO(2) Phillips catalyst, one of the most important catalysts used industrially for olefin polymerization. Interestingly, it was found that Cr(II)/SiO(2) strongly activates CO(2) already at room temperature, making it available for chemicals synthesis. A preliminary attempt in this direction was done by following the...
in this study we have tested the ability of a standard dft computational protocol to reproduce the experimentally obtained stereoselectivity of 26 different c2-symmetric zirconocene catalysts active in propylene polymerization. the catalysts were chosen for their relevance in metallocene catalyzed polymerization of propylene. to this end, primary insertion of both si- and re-propylene enantiofa...
A series of seven new complexes of zirconium and hafnium with bulky ω-aryloxyalkyl substituted indenyl ligands were synthesized and characterized by NMR spectroscopy and elemental analysis. These complexes were activated with methylaluminoxane and tested for homogeneous ethylene polymerization. The zirconium catalysts showed higher activities than their hafnium an...
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