Unraveling the Catalytic Synergy between Ti3+ and Al3+ Sites on a Chlorinated Al2O3: A Tandem Approach to Branched Polyethylene. (21st July 2016)

• Record Type: Journal Article
• Authors: Piovano, Alessandro; Thushara, K. S.; Morra, Elena; Chiesa, Mario; Groppo, Elena
• Is Part Of: Angewandte Chemie. Volume 128:Number 37(2016)
• Page Start: 11369
• Page End: 11372
• Publication Date: 2016-07-21
• Subjects: EPR-Spektroskopie -- Operando-FT-IR-Spektroskopie -- Tandemkatalyse -- Ti3+-Zentren -- Ziegler-Natta-Katalysatoren; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201604136
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: An original step‐by‐step approach to synthesize and characterize a bifunctional heterogeneous catalyst consisting of isolated Ti 3+ centers and strong Lewis acid Al 3+ 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 Al 3+ ions promote ethylene oligomerization through a carbocationic mechanism and activate the Ti 3+ sites for the traditional ethylene coordination polymerization.