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Analyses of Propene and 1-Hexene Oligomers from Zirconocene/MAO Catalysts - Mechanistic Implications by NMR, SEC and MALDI-TOF MS

  • A series of Cp(C5H5)ZrCl2 and Cp2ZrCl2 pre-catalysts (Cp = C5HMe4, C4Me4P, C5Me5, C5H4tBu, C5H3-1,3-tBu2, C5H2-1,2,4-tBu3) together with (C5H5)2ZrCl2 was used for the directed oligomerization of propene and 1-hexene in comparative experiments. Oligomer characterization was carried out by 1H NMR, SEC (GPC), MALDI-TOF MS, cryoscopy and Raman spectroscopy. From 1H NMR the nature and relative ratio of the double-bond end group is determined together with n if every oligomer molecule contains such a double-bond end group. Normally vinylidene double bonds (from -hydrogen elimination) are found. From 1H NMR and MALDI-TOF MS also vinyl end groups (from -methyl elimination) are observed in the case of oligopropenes with (C4Me4P)- (C5H5)ZrCl2 and with the symmetrical methyl containing Cp2ZrCl2 pre-catalysts. The vinylidene/vinyl ratio depends on the ligand and increases from C5HMe4 (65/35) over C4Me4P (61/39) to C5Me5 (9/91). A comparison of n from 1H NMR and SEC together with MALDI-TOF MS showsA series of Cp(C5H5)ZrCl2 and Cp2ZrCl2 pre-catalysts (Cp = C5HMe4, C4Me4P, C5Me5, C5H4tBu, C5H3-1,3-tBu2, C5H2-1,2,4-tBu3) together with (C5H5)2ZrCl2 was used for the directed oligomerization of propene and 1-hexene in comparative experiments. Oligomer characterization was carried out by 1H NMR, SEC (GPC), MALDI-TOF MS, cryoscopy and Raman spectroscopy. From 1H NMR the nature and relative ratio of the double-bond end group is determined together with n if every oligomer molecule contains such a double-bond end group. Normally vinylidene double bonds (from -hydrogen elimination) are found. From 1H NMR and MALDI-TOF MS also vinyl end groups (from -methyl elimination) are observed in the case of oligopropenes with (C4Me4P)- (C5H5)ZrCl2 and with the symmetrical methyl containing Cp2ZrCl2 pre-catalysts. The vinylidene/vinyl ratio depends on the ligand and increases from C5HMe4 (65/35) over C4Me4P (61/39) to C5Me5 (9/91). A comparison of n from 1H NMR and SEC together with MALDI-TOF MS shows that the phospholyl-zirconocenes and (C5HMe4)2ZrCl2 also exhibit chain transfer to aluminium, thereby giving saturated oligomers.zeige mehrzeige weniger

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Metadaten
Autor*innen:Ch. Janiak, K.C.H. Lange, P. Marquardt, Ralph-Peter Krüger, R. Hanselmann
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Macromolecular chemistry and physics
Jahr der Erstveröffentlichung:2002
Verlag:Wiley-VCH Verl.
Verlagsort:Weinheim
Jahrgang/Band:203
Ausgabe/Heft:1
Erste Seite:129
Letzte Seite:138
Freie Schlagwörter:Chain transfer; MALDI; Metallocene catalysts; Oligomers; Polyolefins
DOI:10.1002/1521-3935(20020101)203:1<129::AID-MACP129>3.0.CO;2-C
ISSN:1022-1352
ISSN:1521-3935
Verfügbarkeit des Dokuments:Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")
Bibliotheksstandort:Sonderstandort: Publica-Schrank
Datum der Freischaltung:19.02.2016
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:16.01.2003
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