UiO-66(Ce) metal-organic framework as a highly active and selective catalyst for the aerobic oxidation of benzyl amines

In the present study, UiO-66(Ce) metal-organic framework (MOF) was synthesized by solvothermal method and thoroughly characterized by powder X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), Raman, UV–vis diffuse reflectance spectra (UV-DRS) and scanning electron microscope (SEM) techniques to confirm its formation . The catalytic performance of UiO-66(Ce) was studied in the aerobic oxidation of benzyl amines to their respective imines with high selectivity. Among the various catalysts screened for the aerobic oxidation of benzyl amine (1) to its respective imine (3), UiO-66(Ce) exhibited the highest activity and is due to its high oxophilicity as well as high surface area. The reaction was heterogeneous as shown by hot-filtration test and the activity of the solid is retained up to four reuses. A series of control experiments indicated that the reaction operates through radical mechanism. Substrate scope studies showed that UiO-66(Ce) solid is efficient in promoting the oxidation of benzyl amines and no reaction occurred for aniline and n-butylamine.