Stoichiometric production of aminobenzenes and ketones by photocatalytic reduction of nitrobenzenes in secondary alcoholic suspension of titanium(IV) oxide under metal-free conditions

Abstract

Photocatalytic conversion of nitrobenzenes in 2-propanol suspensions of bare titanium(IV) oxide (TiO2) under various conditions was examined. Aniline and acetone were simultaneously produced almost stoichiometrically from a 2-propanol suspension of TiO2 containing nitrobenzene under deaerated conditions without the use of a precious metal. Nitrobenzenes having another reducible group such as vinyl, chloro and bromo were chemoselectively reduced to corresponding aminobenzenes in 2-propanol suspensions of a TiO2 photocatalyst with an almost stoichiometric amount of acetone. Photocatalytic reduction of nitrobenzene and oxidation of 2-propanol occurred even in the presence of oxygen, and no re-oxidation of anilines occurred.