Synthesis of bifunctional catalysts Al-SBA-15-NH2 with high aluminum content and the catalytic application for different one-pot reactions

Acid-base bifunctional mesoporous catalysts Al-SBA-15-NH2 containing high content of Al and organic amine functional groups have been synthesized through the “pH-adjusting” method. The materials were characterized by X-ray diffraction (XRD), scanning electron micrographs (SEM), transmission electron micrographs (TEM), Fourier-transform infrared spectroscopy (FTIR), IR spectra of pyridine adsorption, NH3-TPD and elemental analysis. Catalytic results showed that 6-Al-SBA-15-NH2 (Si/Al = 6 mol%) was more active than 10-Al-SBA-15-NH2 (Si/Al = 10 mol%) in one-pot deacetalization-Knoevenagel and deacetalization-nitroaldol (Henry) reactions.

Graphical abstractTEM images of the sample of 6-Al-SBA-15-NH2 from parallel direction (a) and perpendicular direction (b). TEM images show a perfect hexagonal pore structure, indicating that the addition of organic function group to the materials has no distinct influence on the morphology of composition. The pore diameter of the functionalized materials estimated from the TEM is around 6-8 nm.Download full-size imageHighlights► Acid-base bifunctionalized Al-SBA-15-NH2 catalysts. ► Synthesized by postsynthetic grafting. ► Possessing high catalytic activity for one-pot cascade reactions.