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Title: | Preparation of crystal-like periodic mesoporous phenylene-silica derivatized with ferrocene and its use as a catalyst for the oxidation of styrene |
Author: | Gomes, Ana C. Ferreira, Maria J. Bruno, Sofia M. Bion, Nicolas Ferreira, Paula Valente, Anabela A. Pillinger, Martyn Rocha, Joao Goncalves, Isabel S. |
Keywords: | MOLECULAR-SCALE PERIODICITY BENZENE-SILICA HETEROGENEOUS CATALYST SELECTIVE OXIDATION HYBRID MATERIAL AQUEOUS-MEDIUM ORGANIC GROUPS CHANNEL WALLS PORE WALLS ORGANOSILICAS |
Issue Date: | 2013 |
Publisher: | ROYAL SOC CHEMISTRY |
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. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/20237 |
DOI: | 10.1039/c3dt51931g |
ISSN: | 1477-9226 |
Publisher Version: | 10.1039/c3dt51931g |
Appears in Collections: | CICECO - Artigos |
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Preparation of crystal-like periodic mesoporous phenylene-silica derivatized with ferrocene and its use as a catalyst for the oxidation of styrene_10.1039c3dt51931g.pdf | 1.37 MB | Adobe PDF |
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