Direct amination of benzene to aniline with H2O2 and NH3·H2O over Cu/SiO2 catalyst

Abstract

The direct amination of benzene to aniline with H₂O₂ and NH₃·H₂O was studied using a series of Cu/SiO₂ catalysts with mesoporous structures under mild conditions, and an acceptable yield (5.4%) and selectivity (74.0%) to aniline was obtained. Ultraviolet-visible diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated that some of the Cu atoms were incorporated into the mesoporous silica network forming Cu–O–Si species, which enabled the selective activation of the N–H bond of NH₃. The medium-strong acid sites were beneficial for the amination reaction. The concentration of the reactants was found to be another critical factor for aniline formation. The amination of the aromatic ring of substituted benzenes was also investigated under the optimized conditions.