Photocatalytic oxidation of dinitronaphthalenes: theory and experiment.
A combination of photocatalytic oxidation experiments and quantum mechanical calculations was used in order to describe the mechanism and the nature of the photocatalytic oxidation reactions of dinitronaphthalane isomers and interprete their reactivities within the framework of the Density Functional Theory (DFT). The photocatalytic oxidation reactions of three dinitronaphthalene isomers, 1,3-dinitronaphthalene, 1,5-dinitronaphthalene and 1,8-dinitronaphthalene in the presence of TiO(2) Degussa P-25 grade were investigated experimentally. The reactions were carried out in a Solarbox photoreactor equipped with a Xenon lamp. The removal of the individual substrates was followed by means of a gas chromatographic method. Nonpurgable organic carbon contents of the samples were determined by means of the catalytic oxidation method using Total Organic Carbon analyzer. With the intention of determining the best reactivity descriptors to explain the differences in the photocatalytic oxidation rates in terms of the molecular properties, geometry optimizations of the compounds were performed with the Density Functional Theory DFT at B3LYP/6-31G( *) level. In order to take the effect of adsorption on the oxidation rate, a cluster Ti(9)O(18) cut from the anatase bulk structure was modeled. The binding energies for the compounds were calculated by using the double-zeta basis set. Global hardness, softness, Fukui functions, local hardness-softness and local softness differences were calculated. The results show that the reactions investigated are orbital-controlled and electrophilic in nature. Local DFT descriptors reflect the reactivities of the dinitronaphthalene isomers better than the global ones, due to the differences in their adsorptive capacities.
Bekbolet
Miray
M
Bogazici University, Institute of Environmental Sciences, 34342 Bebek, Istanbul, Turkey.
Cinar
Zekiye
Z
Kiliç
Murat
M
Uyguner
Ceyda Senem
CS
Minero
Claudio
C
Pelizzetti
Ezio
E
D002384:Catalysis; D004785:Environmental Pollutants / Q000737:chemistry / Q000528:radiation effects*; D008956:Models, Chemical; D009281:Naphthalenes / Q000737:chemistry / Q000528:radiation effects*; D009574:Nitro Compounds / Q000737:chemistry / Q000528:radiation effects*; D011789:Quantum Theory; D014025:Titanium / Q000737:chemistry
D004785:Environmental Pollutants; D009281:Naphthalenes; D009574:Nitro Compounds; C009495:titanium dioxide; C073242:1,3-dinitronaphthalene; D014025:Titanium; C541501:1,8-dinitronaphthalene; C429684:1,5-dinitronaphthalene