Nitridation of MgO-loaded MCM-41 and its beneficial applications in base-catalyzed reactions

Nitrogen-containing MgO-MCM-41 solid base material is prepared by nitridation of MgO-loaded mesoporous MCM-41. The ordered mesoporous structure and high surface area of MCM-41 are well preserved after MgO impregnation and nitridation, as proved by the XRD, TEM and nitrogen adsorption/desorption analysis. FTIR spectra the bridging –NH– groups and terminal –NH2 groups are incorporated into the framework of MgO-MCM-41 by nitridation, and the base strength is expected to be enhanced due to the replacement of oxygen by nitrogen with lower electronegativity. FTIR spectra with the adsorption of different probe molecules, e.g. CO, CD3CN and 13CO2, are employed for the characterization of surface acidic–basic properties of MgO-MCM-41 before and after nitridation. It is revealed that the acidic hydroxyls in MgO-MCM-41 are greatly reduced through nitridation process. Compared with MgO-MCM-41, the nitridized MgO-MCM-41 material exhibits improved basic catalytic performances in Knoevenagel condensation reaction, Claisen–Schmidt reaction and dehydrogenation reaction of 2-propanol.

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► Promising solid base catalyst MgO-MCM-41-N prepared by nitridation of MgO-loaded MCM-41.
► The acidic hydroxyls in parent MgO-MCM-41 greatly reduced through nitridation.
► MgO-MCM-41-N with enhanced basic catalytic properties.