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UV‐Assisted Removal of Inactive Peroxide Species for Sustained Epoxidation of Cyclooctene on Anatase TiO 2
Author(s) -
Yang Changjun,
Lang Xianjun,
Ma Wanhong,
Chen Chuncheng,
Ji Hongwei,
Zhao Jincai
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201400258
Subject(s) - cyclooctene , anatase , peroxide , catalysis , photocatalysis , photochemistry , chemistry , raman spectroscopy , hydrogen peroxide , radical , organic chemistry , physics , optics
Epoxidation of olefins with H 2 O 2 is one of the most important reactions in organic synthesis. We found that anatase TiO 2 can be a good catalyst for the epoxidation of cyclooctene with H 2 O 2 at room temperature. However, the catalyst deactivated quickly in the presence of excess amount of H 2 O 2 because of the formation of inactive side‐on Ti‐η 2 ‐peroxide species on the surface of TiO 2 , the presence of which was confirmed by isotope‐labelled resonance UV Raman spectroscopy and kinetics studies. Interestingly, the epoxidation reaction could be dramatically accelerated under irradiation of UV light with λ ≥350 nm. This phenomenon is attributed to the photo‐assisted removal of the inactive peroxide species, through which the active sites on the surface of anatase TiO 2 are regenerated and the catalytic epoxidation of cyclooctene with H 2 O 2 is resumed. This finding provides an alternative for sustained epoxidation reactions on TiO 2 at room temperature. Moreover, it also has significant implications on the deactivation pathway and possible solutions in Ti‐based heterogeneous catalysis or photocatalysis.