Unraveling the Catalytic Synergy between Ti3+ and Al3+ Sites on a Chlorinated Al2O3: A Tandem Approach to Branched Polyethylene

An original step‐by‐step approach to synthesize and characterize a bifunctional heterogeneous catalyst consisting of isolated Ti3+ centers and strong Lewis acid Al3+ sites on the surface of a chlorinated alumina has been devised. A wide range of physicochemical and spectroscopic techniques were empl...

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Bibliographic Details
Published in:Angewandte Chemie 2016-09, Vol.128 (37), p.11369-11372
Main Authors: Piovano, Alessandro, Thushara, K. S., Morra, Elena, Chiesa, Mario, Groppo, Elena
Format: Article
Language:English
Subjects:
Chemistry
EPR-Spektroskopie
Operando-FT-IR-Spektroskopie
Polyethylene
Tandemkatalyse
Ti3+-Zentren
Ziegler-Natta-Katalysatoren
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Summary:An original step‐by‐step approach to synthesize and characterize a bifunctional heterogeneous catalyst consisting of isolated Ti3+ centers and strong Lewis acid Al3+ sites on the surface of a chlorinated alumina has been devised. A wide range of physicochemical and spectroscopic techniques were employed to demonstrate that the two sites, in close proximity, act in a concerted fashion to synergistically boost the conversion of ethylene into branched polyethylene, using ethylene as the only feed and without any activator. The coordinatively unsaturated Al3+ ions promote ethylene oligomerization through a carbocationic mechanism and activate the Ti3+ sites for the traditional ethylene coordination polymerization. Seite an Seite: Verzweigtes Polyethylen wurde mithilfe eines Katalysators hergestellt, der aus Ti3+‐ und Al3+‐Zentren auf chloriertem Aluminiumoxid besteht. Nach spektroskopischen und physikochemischen Daten fördern die katalytischen Zentren die Olefinumwandlung synergetisch.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201604136