Alcohol-Selective Oxidation in Water under Mild Conditions via a Novel Approach to Hybrid Composite Photocatalysts.
The oxidation of alcohols to carbonyl compounds in a clean fashion (i.e., with water as a solvent or under solvent-free conditions, and using O2 or H2O2 as the primary oxidant) is the subject of considerable research efforts. A new approach for the selective oxidation of soluble aromatic alcohols in water under mild conditions via a novel composite photocatalyst has been developed. The catalyst is synthesized by grafting 4-(4-(4-hydroxyphenylimino)cyclohexa-2,5dienylideneamino)phenol and silver nanoparticles onto the surface of moderately crystalline titanium dioxide. The titanium dioxide-based composite was first extensively characterized and then employed in the catalytic oxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde under UV irradiation in water at room temperature. The corresponding aldehyde was obtained with unprecedented high selectivity (up to 86 %). The method is general and opens the route to fabrication of photocatalytic composites based on titanium dioxide functionalized with shuttle organic molecules and metal nanoparticles for a variety of oxidative conversions.
Egyptian Petroleum Research Institute 1 Ahmed El-Zomor St. 11727 Cairo Egypt; "Schiavello-Grillone" Photocatalysis Group DEIM Università degli Studi di Palermoviale delle Scienze 90128 Palermo Italy; Istituto per lo Studio dei Materiali Nanostrutturati CNR Via U. La Malfa 153-90146 Palermo Italy.
Ali
A
Abd-Elaal
"Schiavello-Grillone" Photocatalysis Group DEIM Università degli Studi di Palermo viale delle Scienze 90128 Palermo Italy.
Francesco
F
Parrino
Istituto per lo Studio dei Materiali Nanostrutturati CNR Via U. La Malfa 153-90146 Palermo Italy.
Rosaria
R
Ciriminna
"Schiavello-Grillone" Photocatalysis Group DEIM Università degli Studi di Palermo viale delle Scienze 90128 Palermo Italy.
Vittorio
V
Loddo
"Schiavello-Grillone" Photocatalysis Group DEIM Università degli Studi di Palermo viale delle Scienze 90128 Palermo Italy.
Leonardo
L
Palmisano
Istituto per lo Studio dei Materiali Nanostrutturati CNR Via U. La Malfa 153-90146 Palermo Italy.
Mario
M
Pagliaro
alcohol oxidation; composites; nanostructures; photocatalysis; titanium dioxide