نتایج جستجو برای: metallocene catalyst
تعداد نتایج: 44388 فیلتر نتایج به سال:
Research on "post-metallocene" polymerization catalysis ranges methodologically from fundamental mechanistic studies of polymerization reactions over catalyst design to material properties of the polyolefins prepared. A common goal of these studies is the creation of practically useful new polyolefin materials or polymerization processes. This Review gives a comprehensive overview of post-metal...
s of Doctor’s Thesises Effect of “Topotactic” Reduction Products on Catalytic Activity of Metallocene Catalyst for Olefin Polymerization Satoru Yamada † (Department of Chemistry for Materials)
Long-chain branches and narrow molecular weight distribution is a novel structure combination in polyethene, which has only been possible to achieve with single-center catalysis. Long-chain branches, even at very low concentrations, have a strong effect on the polymer melt behavior and, thereby, the processing properties. This work deals with ethene polymerization using group IV metallocene cat...
a variety of group 4 metal catalytic systems (c2-symmetric {ebthi}-, {sbi}-type zirconocene complexes (c2-1–4); c1-symmetric (c1-5–8) and cs-symmetric (cs-9) {cp/flu}-type zirconocene complexes; cp*2zrcl2 (cp* 2-10)), half-metallocene complexes (cpticl3, hm-11), constrained-geometry (cgc-12) titanium catalysts) and post-metallocene catalysts (dow’s ortho-metallated amido-pyridino hafnium comple...
Olefin polymerization catalysis is a domain of major research activity. For the last decade, much of this research has been focused in the area of metallocene catalysis, which has been at the front line in driving important technology renewal in the polyolefins industry. Developments in metallocene catalysis have instigated much trade press discussion, and now emerging nonmetallocene catalyst s...
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 ...
Metallocene and ansa-metallocene complexes of group 3 metals and the Lanthanides have shown to be effective catalysts for a number of chemical reactions. These include alkene polymerization, hydrosilation, hydroboration, hydrogenation and hydroamination. The coordinatively unsaturated, monomeric permethylyttrocene complexes in particular have proven to be highly effective for carrying out these...
bis(indenyl)zirconium dichloride as a catalyst was synthesized using a modified method at the room temperature. polymerization of ethylene and copolymerization of ethylene and propylene were carried out by this metallocene catalyst. ethylene propylene (p/e) feed ratios of 0.25, 0.5, 1, and 2 were employed into the copolymerization systems. copolymerization conditions like cocatalyst/catalyst ra...
Several types of hybrid catalysts are made through mixing of 4th generation Ziegler-Natta (ZN) and (2-PhInd)2ZrCl2 metallocene catalysts using triethylaluminum (TEA) as coupling agent. Response surface methodology (RSM) is used to evaluate the interactive effects of different parameters including amounts of metallocene and TEA and temperature on metallocene loading. Analyzing the amounts of Al...
several types of hybrid catalysts are made through mixing of 4th generation ziegler-natta (zn) and (2-phind)2zrcl2metallocene catalysts using triethylaluminum (tea) as coupling agent. response surface methodology (rsm)is used to evaluate the interactive effects of different parameters including amounts of metallocene and tea andtemperature on metallocene loading. analyzing the amounts of al and...
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