Solvent Free Highly Dispersed Zinc Oxide within Confined Space of Al-Containing SBA-15 as an Efficient Catalyst for Knoevenagel Condensation

A mesoporous silica-supported zinc oxide catalyst was successfully synthesized by directly grinding zinc nitrate into the as-prepared Al-Containing SBA-15 occluded with template and characterized by powder X-ray diffraction (XRD), BET nitrogen adsorption-desorption methods, IR spectroscopy, transmission electron microscopy and diffuse reflectance UV-Vis spectroscopy. This solvent-free method not only saves the time and energy, but also enables a high dispersion of zinc oxide without pore blocking in the channels of mesoporous silica. The XRD and TEM analyses show that textural properties of Al-SBA-15 retained after coating process. The resulting material was successfully applied as a heterogeneous catalyst for Knoevenagel Condensation in good to excellent yields under mild conditions.