| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 54898 | Catalysis Today | 2013 | 11 Pages |
Immobilization of chromium complexes on modified silica support was achieved via two different synthetic routes using 3-aminopropyl triethoxysilane (APTS) as a linking group. The FTIR spectra, elemental and solid-state NMR analyses demonstrated incorporation of amine functional groups on the surface of the APTS-functionalized silica support, which was further confirmed by 29Si solid-state CP MAS NMR spectroscopy.Oxidation of cyclohexene was carried out over the chromium complex supported on organically modified silica using H2O2 as an oxidant under various conditions and different atmospheres viz. oxygen, nitrogen and air. The supported catalysts exhibited excellent activity (>94%) after 6 h reaction time under O2 atmosphere using THF as solvent. The catalysts showed high chemoselectivity towards formation 2-cyclohexen-1-ol and 2-cyclohexen-1-one. Activity of the immobilized catalysts remains nearly the same after three consecutive cycles, suggesting the true heterogeneous nature of the catalyst.
Graphical abstract.Figure optionsDownload full-size imageDownload high-quality image (129 K)Download as PowerPoint slideHighlights► Two different synthetic routes used to synthesize new active heterogeneous catalyst. ► The structure of the catalysts confirmed by different physico-chemical techniques. ► Excellent activity achieved after 6 h under O2 in THF. ► These catalysts were stable and recovered. ► These catalysts were reused three times with no significant loss in activity.
