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Direct Observation of Radicals in the Activation of Ziegler–Natta Catalysts
Author(s) -
Risse Thomas,
Schmidt Jörg,
Hamann Heiko,
Freund HansJoachim
Publication year - 2002
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/1521-3773(20020503)41:9<1517::aid-anie1517>3.0.co;2-u
Subject(s) - radical , natta , catalysis , chemistry , activation energy , alkyl , photochemistry , spectroscopy , titanium , polymer chemistry , organic chemistry , polymerization , physics , quantum mechanics , polymer
Are radicals involved in the activation of a heterogeneous Ziegler–Natta catalyst? The activation of titanium centers in an active Ziegler–Natta model system initiated by alkyl aluminum compounds has been shown by ESR spectroscopy under ultrahigh‐vacuum conditions to proceed, in the case of trimethylaluminum, by a radical mechanism (see picture). In contrast, no indication of radical production is found when the ethyl derivative is used for activation.