Effects of the precatalyst structure and the Mg-containing third-component on cyclo-oligomerization of ethene
2004 (English)In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, Vol. 216, no 1, 13-17 p.Article in journal (Refereed) Published
The catalytic cyclo-oligomerization of ethene by metallocene complexes Cp2ZrCl2 with Et3Al as cocatalyst in the presence of Mg-containing third-components is described. Under optimal conditions (Cp2ZrCl2/Et3Al/Et2Mg = 1:100:10, 150degreesC, P(C2H4) = 1.4 MPa) the reaction afforded 51% of cyclic oligomers, including exo-methylenecyclopentane (41%) and a small amount of methylcyclopentane (3%), 1-methyl-1-ethylcyclopentane (4%) and vinylcyclohexane (3%), along with usual open-chain alkenes. When the pi-ligand was changed to eta(5)-pentamethylcyclopentadienyl and indenyl (Ind) or Cp2TiCl2 was used in place of Cp2ZrCl2, the selectivity of exo-methylenecyclopentane dropped dramatically to 1-8%. In contrast, the catalytic reactions by post-metallocene complexes (LZrCl2)-Zr-2 (L-2 = salen, salphen) under identical conditions generated open-chain alkenes exclusively. A zirconacyclopentane mechanism is proposed to explain the products formed in cyclo-oligomerization of ethene.
Place, publisher, year, edition, pages
2004. Vol. 216, no 1, 13-17 p.
zirconocene complexes, ethene oligomerization, cyclo-oligomerization, carbocyclic compounds, monosubstituted alkenes, zirconocene complexes, crystal-structures, alkyl-alkene, zirconium, ethylene, derivatives, catalysts, olefins, cyclization
IdentifiersURN: urn:nbn:se:kth:diva-23457ISI: 000221708400002OAI: oai:DiVA.org:kth-23457DiVA: diva2:342155
QC 201005252010-08-102010-08-10Bibliographically approved