Catalyst Speciation during ansa-Zirconocene-Catalyzed Polymerization of 1-Hexene Studied by UV-vis Spectroscopy—Formation and Partial Re-Activation of Zr-Allyl Intermediates †
نویسندگان
چکیده
منابع مشابه
Metallocene-catalyzed alkene polymerization and the observation of Zr-allyls.
Single-site polymerization catalysts enable exquisite control over alkene polymerization reactions to produce new materials with unique properties. Knowledge of catalyst speciation and fundamental kinetics are essential for full mechanistic understanding of zirconocene-catalyzed alkene polymerization. Currently the effect of activators on fundamental polymerization steps is not understood. Prog...
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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...
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The biphenyl-bridged. chiral zirconocene complex rac-2.2' -biphenyl-bis( 3.4-dimethylcyclopentadienyl I zirconium dichloride catalyzes the reaction of 1.6and 1,7 -dienes with excess dibutyl magnesium to bis( butyl-magnesio-methyl '-substituted cycloalkanederivatives. Analogous reactions occur with butyl magnesium chloride and with heteroatom-t.:Ontaining dienes. The preference of 1.6-dienes for...
متن کاملZirconium-allyl complexes as resting states in zirconocene-catalyzed α-olefin polymerization.
UV-vis spectroscopic data indicate that zirconocene cations with Zr-bound allylic chain ends are generally formed during olefin polymerization with zirconocene catalysts. The rates and extent of their formation and of their re-conversion to the initial pre-catalyst cations depend on the types of zirconocene complexes and activators used.
متن کاملEffects of FeCl3 doping on the performance of MgCl2/TiCl4/DNPB catalyst in 1-hexene polymerization
The aim of this study was to examine the effect of catalyst doping on the performance of MgCl2. EtOH/TiCl4 catalyst system. In this regard, a series of undoped as well as FeCl3-doped catalysts was prepared and employed in 1-hexene polymerization. A modified catalyst containing 10 wt. % of FeCl3 dopant demonstrated the highest activity, with 32% activity increase compared to unmodified one, amon...
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ژورنال
عنوان ژورنال: Polymers
سال: 2019
ISSN: 2073-4360
DOI: 10.3390/polym11060936