An investigation into the Ti-grafting structure on MCM-41 and epoxidation catalysis

Qingchun Yuan*, Anke Hagen, Frank Roessner

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

The structure of titanium species grafted on a purely siliceous MCM-41 and their catalysis in the epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP) were investigated. FT-IR, XANES and UV-vis were used for the examination of the Ti-grafted MCM-41. The results indicated that the titanium atoms are grafted on the wall surface of the MCM-41 by four-fold coordination. The four-fold coordinated titanium species are mainly grafted by two or one -O-Si-O- bridges on the MCM-41, resulting in so-called bipodal or monopodal titanium centres in partially polymerised states. The ratio of monopodal to bipodal titanium increases with the increase in Ti-content. These partially polymerised titanium species considered as catalytic active centres have high activity and selectivity in the epoxidation reaction. The used Ti-grafted MCM-41 samples were regenerated by heating in nitrogen or air atmosphere. The regeneration in nitrogen atmosphere gives samples with significantly higher catalytic activity than in air.

Original languageEnglish
Pages (from-to)81-87
Number of pages7
JournalApplied Catalysis A: General
Volume303
Issue number1
DOIs
Publication statusPublished - 18 Apr 2006

Keywords

  • Epoxidation
  • Regeneration
  • Ti-content
  • Ti-grafted MCM-41 structure
  • UV-vis

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