Activation of rac-Me2Si(ind)2ZrCI2 by Methylalumoxane Modified by Aluminum Alkyls: An EPR Spin-Probe, IH NMR, and Polymerization Study
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منابع مشابه
Propene-cycloolefin polymerization
Highly active metallocenes and other single site catalysts have opened up the possibility of polymerizing cycloolefins such as norbornene (N) or of copolymerizing them with ethene (E) or propene (P). The polymers obtained show exciting structures and properties. E-N copolymers are industrially produced materials, with variable and high glass transitions depending on the wide range of their micr...
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Addition of 1-hexene to methylalumoxane-activated catalyst systems based on rac-Me(2)Si(ind)(2)ZrMe(2) causes, concurrent with polyhexene formation and diminution of the otherwise prevalent cation [rac-Me(2)Si(ind)(2)Zr(mu-Me)(2)AlMe(2)](+), formation of a hitherto unobserved species [rac-Me(2)Si(ind)(2)Zr(mu-R)(mu-Me)AlMe(2)](+), where R is a Zr-bound polyhexyl chain. As hexene is increasingly...
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Reaction of Me,Si(lnd),ZrCI, with excess methylalumoxane (MAO) gives rise to ion pairs containing zirconocenium cations of the type [Me2Si(lnd)2ZrMe]+ in contact with two types of anions, MeMAOA and MeMAOB -, which differ in their coordinative strengths: More strongly coherent contact-ion pairs [Me2Si(lnd)2 ZrMe+'>MeMAOB -] are converted by a sufficiently high excess of MAO to more easily separ...
متن کاملRecent advances in the polymerization of butadiene over the last decade
The stereospecific polymerization of conjugated dienes began in 1954 with the first catalysts obtained by combining TiCl4 or TiCl3 with aluminum-alkyls, i.e. the catalytic systems previously employed for ethylene and propylene polymerizations. Subsequently, many other catalytic systems were obtained and examined by a combination of transition metal or lanthanide compounds with appropriate alkyl...
متن کاملQuasi-Living Polymerization of Propene with an Isotactic-Specific Zirconocene Catalyst.
Propene polymerization with isotactic (iso)-specific C₂-symmetric rac-Me₂Si(2-Me-Benz(e)-Ind)₂ZrCl₂ (1) and rac-Me₂Si(2-Me-4-Ph-1-Ind)₂ZrCl₂ (2) were conducted under various conditions for achieving iso-specific living polymerization of propene. When Complex 1 was activated with trialkylaluminum-free modified methylaluminoxane (dMMAO) at -40 °C, the number-average molecular weight (Mn) linearly...
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تاریخ انتشار 2013