Homo- and Copolymerizations of Ethylene and Norbornene Using Bis(-ketoamino) Titanium Catalysts Containing Pyrazolone Rings
نویسندگان
چکیده
A series of bis(β-ketoamino) titanium complexes containing pyrazolone rings (1–3) have been synthesized, characterized, and used as precursors for homoand copolymerization of ethylene and norbornene. The titanium complexes activated with methylaluminoxane (MAO) exhibited good activities for homopolymerization of ethylene (E) to produce linear polyethylenes (PEs). Ethylene–norbornene copolymers (E–N) were also prepared by these catalysts with moderate activities, and influences of ligand substituents and norbornene addition on copolymer microstructure were studied in detail. Microstructure analysis of the E–N copolymers by 13C NMR and differential scanning calorimetry (DSC) techniques showed that alternating (ENEN) and isolated (ENEE) norbornene predominately appeared in the copolymer chain, and the NN dyad and NNN triad sequences were also present in the copolymers obtained by the less bulky catalyst 1.
منابع مشابه
[ONNO]-type amine bis(phenolate)-based vanadium catalysts for ethylene homo- and copolymerization*
The synthesis and solution and solid-state structural characterization of a family of amine bis(phenolate) [ONNO]-vanadium complexes is reviewed. These compounds have oxi dation states ranging from vanadium(II) to vanadium(V), and were evaluated as olefin polymerization catalysts. In association with EtAlCl2 cocatalyst, we studied the homo polymerization of ethylene, propene, and 1-hexene, as w...
متن کاملDesign of Efficient Molecular Catalysts for Synthesis of Cyclic Olefin Copolymers (COC) by Copolymerization of Ethylene and -Olefins with Norbornene or Tetracyclododecene
Selected results for the synthesis of cyclic olefin copolymers (COCs)—especially copolymerizations of norbornene (NBE) or tetracyclododecene (TCD) with ethylene and α-olefins (1-hexene, 1-octene, 1-dodecene)—using group 4 transition metal (titanium and zirconium) complex catalysts have been reviewed. Half-titanocenes containing an anionic ancillary donor ligand, Cp’TiX2(Y) (Cp’ = cyclopentadien...
متن کاملHomo- and Copolymerization of Ethylene and Norbornene with Anilido–Imine Chromium Catalysts
A series of anilido–imine chromium complexes have been used as precursors to catalyze homoand copolymerization of ethylene and norbornene. The chromium complexes activated with methylalumoxane (MAO) exhibit good activities for homopolymerization of ethylene (E) to produce linear polyethylene and moderate activities for norbornene (N) polymerization to afford vinyl-type polynorbornene. Ethylene–...
متن کاملConstrained Geometry Organotitanium Catalysts Supported on Nanosized Silica for Ethylene (co)Polymerization.
Supported olefin polymerization catalysts can prevent reactor-fouling problems and produce uniform polymer particles. Constrained geometry complexes (CGCs) have less sterically hindered active sites than bis-cyclopentadienyl metallocene catalysts. In the literature, micrometer-sized silica particles were used for supporting CGC catalysts, which might have strong mass transfer limitations. This ...
متن کاملBis(Imino) Pyridyl Iron Complexes: the Effect of Polymerization Conditions on Activities and Thermal Behaviors of Polyethylene
Two late transition metal catalysts based on 2,6-bis(imino)pyridine iron(II) were synthesized by introducing methyl substitution (catalyst A) and t-Butyl substitution (catalyst B) at the ortho position of the aryl rings of the ligand. Comparative ethylene polymerizations using the catalysts showed quiet different behaviors. The activity of catalyst A was higher than that of catalyst B in all of...
متن کامل