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Zirconium Catalyst (zirconium + catalyst)

Distribution by Scientific Domains

Polymers and Materials Science	80%

Selected Abstracts

ChemInform Abstract: Enantioselective Mannich-Type Reactions Using a Novel Chiral Zirconium Catalyst for the Synthesis of Optically Active ,-Amino Acid Derivatives.

CHEMINFORM, Issue 1 2001
Haruro Ishitani
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Synthesis of a new zirconium catalyst for ethylene polymerization

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 11 2008
Fabiana De C. Fim
Abstract A novel complex dichlorobis(2-ethyl-3-hydroxy-4-pyrone)zirconium(IV) (ZrCl2(ethylpyrone)2) was synthesized. Complexation of the pyrone ligand to the zirconium was confirmed by UV, 1H and 13C-NMR, and electrochemical studies. NMR showed the presence of four isomers and density functional theory calculations indicated that the main isomer had a cis configuration. The catalyst was shown to be active in ethylene polymerization in the presence of the cocatalyst methylaluminoxane. The highest catalyst activity for the zirconium complex was achieved at Al/Zr = 2500, 70 °C and when a small concentration of catalyst was used (1 ,mol). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3830,3841, 2008 [source]

Efficient and tailored polymerization of olefins and styrene by metallocene catalysts

MACROMOLECULAR SYMPOSIA, Issue 1 2003
Walter Kaminsky
Abstract Different optimised new cs -symmetric ansa zirconocenes were used for the homopolymerization of propene - activated by methylaluminoxane (MAO) with an Al : Zr molar ratio of 2000. In a series of experiments, the polymerisation temperature was varied in a range from 0 to 60°C. The obtained syndiotactic polypropenes show highly isotacticities up to rrrr pentads of 98% and melting points of 150°C. Stereoselectivities are sensitive to the monomer concentration, showing decreasing syndiotacticities with decreasing propene concentration due to increasing amount of skipped insertion which is demonstrated for the zirconium catalyst. [source]

Copolymerization of ethylene and N -(vinylphenyl)carbazole with titanium and zirconium catalysts

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2005
Naofumi Naga
Copolymerization of ethylene and N -(vinylphenyl)carbazole (VPC) was investigated with dimethylsilylene(tetramethylcyclopentadienyl)(N-tert -butyl)titanium dichloride (1) and isopropylidenebis(indenyl)zirconium dichloride (2) catalysts. The corresponding copolymers were obtained in the copolymerization, and the copolymerization behavior and structure of the resulting copolymer were studied. [source]

Highly active copolymerization of ethylene with 10-undecen-1-ol using phenoxy-based zirconium/methylaluminoxane catalysts

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2005
Xiaofan Zhang
Abstract Activated with methylaluminoxane (MAO), phenoxy-based zirconium complexes bis[(3- tBu-C6H3 -2-O)-CHNC6H5]ZrCl2, bis[(3,5-di- tBu-C6H2 -2-O)-PhCNC6H5] ZrCl2, and bis[(3,5-di- tBu-C6H2 -2-O)-PhCN(2-F-C6H4)]ZrCl2 for the first time have been used for the copolymerization of ethylene with 10-undecen-1-ol. In comparison with the conventional metallocene, the phenoxy-based zirconium complexes exhibit much higher catalytic activities [>107 g of polymer (mol of catalyst),1 h,1]. The incorporation of 10-undecen-1-ol into the copolymers and the properties of the copolymers are strongly affected by the catalyst structure. Among the three catalysts, complex c is the most favorable for preparing higher molecular weight functionalized polyethylene containing a higher content of hydroxyl groups. Studies on the polymerization conditions indicate that the incorporated commoner content in the copolymers mainly depends on the comonomer concentration in the feed. The catalytic activity is slightly affected by the Al(MAO)/Zr molar ratio but decreases greatly with an increase in the polymerization temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5944,5952, 2005 [source]