论文成果
Effects of the precatalyst structure and the Mg-containing third-component on cyclo-oligomerization of ethene
  • 点击次数:
  • 论文类型:期刊论文
  • 发表时间:2004-07-01
  • 发表刊物:JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
  • 收录刊物:Scopus、SCIE、EI
  • 文献类型:J
  • 卷号:216
  • 期号:1
  • 页面范围:13-17
  • ISSN号:1381-1169
  • 关键字:zirconocene complexes; ethene oligomerization; cyclo-oligomerization; carbocyclic compounds
  • 摘要: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. (C) 2004 Elsevier B.V. All rights reserved.

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