One-pot synthesis of imine from benzyl alcohol and nitrobenzene on visible-light responsive CdS–TiO2 photocatalysts

Abstract

The one-pot synthesis of imine (N-benzylideneaniline) from benzyl alcohol and nitrobenzene was studied on the CdS–TiO₂ photocatalyst under visible-light irradiation (λ > 420 nm) at 298 K. The photocatalytic activity strongly depends on the loadings of CdS on the TiO₂, and the preferred amount of CdS was 15 wt%. Photo-electrochemical investigations were also incorporated to demonstrate the reaction mechanism: the CdS is photosensitized by visible-light irradiation, and an effective hole–electron separation is generated in the hetero-junction between the CdS and TiO₂. It was also confirmed that the photocatalytic oxidation of benzyl alcohol proceeds over the CdS surface, while the hydrogenative reduction of nitrobenzene into aminobenzene proceeds over the TiO₂ surface. Moreover, the production of imine proceeded efficiently by the successive condensation of benzaldehyde and aminobenzene on the catalyst surface under dark conditions.