A reusable Mn(ii)-dampy-MCM-41 system for single step amination of benzene to aniline using hydroxylamine

Abstract

Reaction methodology for C–H bond amination of benzene catalyzed by Mn(II)-dien (ampy) immobilized organo modified MCM-41 in the presence of hydroxylamine in acetic acid–water medium is described. The organic–inorganic hybrid heterogeneous catalyst achieves high catalytic activity and selectivity for one step amination of benzene. Characterization of the immobilized catalyst by powder X-ray diffraction (XRD), N₂ adsorption–desorption, CP MAS NMR spectroscopy (¹³C and ²⁹Si), Fourier transform infrared spectroscopy (FT-IR) and diffuse reflectance UV–Vis spectroscopy demonstrates the successful grafting of the complex into functionalized mesoporous silica and that the mesostructure has not been destroyed in the multistep synthetic procedure. The variation of reaction conditions such as solvent, temperature, time, catalyst concentration etc. is well demonstrated to achieve high catalytic activity. Moreover, the anchored catalyst can be recovered and reused for multiple cycles without appreciable loss in catalytic activity, which is an alternative to the conventional industrial process.