100% selective yield of m-nitroaniline by rutile TiO2 and m-phenylenediamine by P25-TiO2 during m-dinitrobenzene photoreduction

Photoreduction of m-dinitrobenzene (25 mu mol) in the deaerated aqueous iso-propanol exhibits 100% selective yield of m-nitroaniline (25 mu mol) by rutile TiO2 (50 mg) or m-phenylenediamine (25 mu mol) by P25-TiO2 separately under 8 and 4 h of UV light irradiation (125W Hg arc, 10.4 mW/cm(2)), respectively. It revealed that insertion of a second -NO2 in nitrobenzene ring has an important role in expediting -NO2 reduction to -NH2 as compared to a negligible reduction of nitrobenzene under similar conditions, indicating that electron withdrawing groups lower the electron density on -NO2 present on meta position and favor quick reduction of the -NO2 group. (C) 2014 Elsevier B.V. All rights reserved.