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

摘要

Photoreduction of m-dinitrobenzene (25 umol) in the deaerated aqueous iso-propanol exhibits 100% selective yield of m-nitroaniline (25 umol) by rutile TiO2 (50 mg) or m-phenylenediamine (25 umol) by P25-TiO2 separately under 8 and 4 h of UV light irradiation (125 W 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.