title: Oxidation of aromatic alcohols in irradiated aqueous suspensions of commercial and home-prepared rutile TiO(2): a selectivity study.
abstract: The photocatalytic oxidation of benzyl alcohol (BA) and 4-methoxybenzyl alcohol (MBA) has been performed in pure water by using commercial TiO(2) samples (Sigma-Aldrich, Merck, Degussa P25) and rutile TiO(2) prepared from TiCl(4) at low temperature. Particular attention has been devoted to the identification of the produced aromatic compounds along with the formed CO(2). Oxidation products such as the corresponding aromatic aldehyde and acid, as well as mono- and dihydroxylated aldehydes have been detected. The home-prepared rutile sample showed a marked selectivity towards the formation of the aromatic aldehyde (38 and 60 % for BA and MBA, respectively), resulting in a three- to sevenfold improvement relative to commercial samples, with the only byproduct being CO(2). This catalyst was found to be the most selective in the formation of aldehyde in water. By using the commercial or the calcined home-prepared samples, many hydroxylated aromatic compounds were detected besides the aldehyde and the acid. This finding points to a higher selectivity performance of the home-prepared rutile relative to the commercial TiO(2) samples. Some of the home-prepared samples were also dialysed to check the influence of the presence of Cl(-) species on catalyst reactivity and selectivity. We have attempted to explain the different reaction rate and selectivity observed for MBA and BA.
authors.affiliation: Schiavello-Grillone Photocatalysis Group, Dipartimento di Ingegneria Chimica dei Processi e dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, Palermo, Italy. augugliaro@dicpm.unipa.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Augugliaro
authors.forename: Tullio
authors.initials: T
authors.lastname: Caronna
authors.forename: Vittorio
authors.initials: V
authors.lastname: Loddo
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Marcì
authors.forename: Giovanni
authors.initials: G
authors.lastname: Palmisano
authors.forename: Leonardo
authors.initials: L
authors.lastname: Palmisano
authors.forename: Sedat
authors.initials: S
authors.lastname: Yurdakal
mesh_terms: D000840:Anisoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000528:radiation effects*; D019905:Benzyl Alcohol / Q000138:chemical synthesis* / Q000737:chemistry / Q000528:radiation effects*; D002384:Catalysis; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010777:Photochemistry; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000840:Anisoles; D014867:Water; C009495:titanium dioxide; C066943:anisyl alcohol; D014025:Titanium; D019905:Benzyl Alcohol