authors |
Gomes, AC; Ferreira, MJ; Bruno, SM; Bion, N; Ferreira, P; Valente, AA; Pillinger, M; Rocha, J; Goncalves, IS |
nationality |
International |
journal |
DALTON TRANSACTIONS |
keywords |
MOLECULAR-SCALE PERIODICITY; BENZENE-SILICA; HETEROGENEOUS CATALYST; SELECTIVE OXIDATION; HYBRID MATERIAL; AQUEOUS-MEDIUM; ORGANIC GROUPS; CHANNEL WALLS; PORE WALLS; ORGANOSILICAS |
abstract |
The surface silanol groups in crystal-like mesoporous phenylene-silica have been derivatized with trimethylsilyl, benzyldimethylsilyl and dimethylsilyl(ferrocene) groups by performing a post-synthetic grafting reaction with the corresponding chlorosilane precursors. The success of the grafting procedure was demonstrated by transmission FT-IR spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and C-13 and Si-29 magic-angle spinning (MAS) NMR spectroscopy. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N-2 adsorption data for the modified materials indicated preservation of the mesostructure as well as the molecular-scale periodicity in the pore walls. Ferrocene and the ferrocenyl-modified periodic mesoporous organosilica (PMO) were employed in the catalytic oxidation of styrene at 55 degrees C using either hydrogen peroxide or tert-butylhydroperoxide as an oxidant. The main reaction product was always benzaldehyde (BzCHO), and other products included styrene oxide, benzoic acid and 2-hydroxyacetophenone. Using a styrene : H2O2 molar ratio of 1 : 5, the highest BzCHO yields at 24 h were 65% (85% selectivity) for ferrocene (semibatch conditions involving stepwise addition of H2O2, 1 mol% Fe) and 34% (83% selectivity) for the modified PMO (batch conditions, 0.06 mol% Fe). The modified PMO could be recovered and reused, albeit with a drop in catalytic activity due to partial metal leaching during the first catalytic run. |
publisher |
ROYAL SOC CHEMISTRY |
issn |
1477-9226 |
year published |
2013 |
volume |
42 |
issue |
40 |
beginning page |
14612 |
ending page |
14620 |
digital object identifier (doi) |
10.1039/c3dt51931g |
web of science category |
Chemistry, Inorganic & Nuclear |
subject category |
Chemistry |
unique article identifier |
WOS:000324931400032
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ciceco authors
impact metrics
journal analysis (jcr 2019):
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journal impact factor |
4.174 |
5 year journal impact factor |
3.812 |
category normalized journal impact factor percentile |
90 |
dimensions (citation analysis):
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altmetrics (social interaction):
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