Of Poisons and Antidotes in Polypropylene Catalysis. Issue 30 (31st May 2016)

• Record Type: Journal Article
• Authors: Yu, Yue; Busico, Vincenzo; Budzelaar, Peter H. M.; Vittoria, Antonio; Cipullo, Roberta
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 30(2016)
• Page Start: 8590
• Page End: 8594
• Publication Date: 2016-05-31
• Subjects: alkenes -- hydrogen -- kinetics -- NMR spectroscopy -- polymerization; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201602485
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Quenched‐flow studies of MgCl2 ‐supported Ziegler–Natta catalysts were combined for the first time with 13 C NMR fingerprinting of the nascent polymer and conclusively proved that, depending on the catalyst formulation, propene polymerization can be slowed down significantly by the occurrence of the few regiodefects (2, 1 monomer insertions), changing active sites into dormant sites. Catalysts modified with ethylbenzoate show little dormancy. The more industrially relevant phthalate based catalysts, instead, are highly dormant and require the presence of H2 to counteract the deleterious effect of this self‐poisoning on productivity and stereoselectivity. Abstract : The occasional occurrence of regiodefects in Ziegler–Natta propene polymerizations has long been suspected to change active sites into dormant sites. Herein, combining quenched‐flow kinetic studies with 13 C NMR fingerprinting of the nascent polymer, this behavior is shown to occur, but depends on system formulation. The data also confirm that H2 is a powerful antidote to catalyst self‐poisoning.