Synthesis, characterization and catalytic activity of copper incorporated and immobilized mesoporous MCM-41 in the single step amination of benzene

The paper reports the synthesis, surface and textural characterization of copper and amine modified MCM-41 and its application for the single step amination of benzene to aniline at 70 °C. Varying the amount of Cu different Cu/amine modified MCM-41 samples was synthesized by co-condensation and impregnation method. The samples were characterized by nitrogen adsorption–desorption, X-ray powder diffraction, Fourier-transform infrared spectroscopy (FT-IR), 29Si magic-angle spinning (MAS) and 13C Nuclear Magnetic Resonance (NMR) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). X-ray diffraction patterns indicate that the modified materials retain the standard MCM-41 structure. FT-IR and DRS results indicated that Cu and amino groups are incorporated into the Si–O framework and frame wall respectively. NMR showed higher degree of condensation of materials in framework position. Cu-amine-MCM-41 samples showed significant catalytic activity for single step amination of benzene in acetic acid–water medium under mild reaction conditions using hydroxylamine as aminating agent. The Cu-amine-MCM-41 (Si/Cu = 20) showed highest benzene conversion (72.2%) and 100% selectivity for aniline.

Graphical abstractCu-amine-MCM-41 samples show good activity for single step liquid phase amination of benzene to aniline. The 20Cu-amine modified sample shows highest catalytic activity having 72.2% benzene conversion and 100% aniline selectivity. Cu and amine modified samples prepared by co-condensation method show better activity than samples prepared by impregnation technique and that of without amine.Figure optionsDownload full-size imageDownload high-quality image (78 K)Download as PowerPoint slide