Preparation and characterization of mesostructured Zr-SBA-16: efficient Lewis acidic catalyst for Hantzsch reaction

Mesostructured Zr-SBA-16 (3D cubic arrangement, Im3m space group) with different Si/Zr ratio was successfully synthesized by using Pluronic F127 triblock copolymer and n-butanol as a structure directing agent. Successful incorporation of Zr4+ ions was achieved without any pH adjustments up to ~6.5 wt% of Zr loading. Different analytical techniques such as SAXS, N2-physisortion and HR-TEM were used to ascertain the structure of Zr-SBA-16 samples whereas, diffuse reflectance UV–Vis, pyridine adsorbed FTIR and NH3 desorbed TPD methods were assessed to understand the nature of Zr incorporation. The Lewis acidity of Zr-SBA-16 was explored in the synthesis of Hantzsch 1,4-dihydropyridine derivatives via condensation of substituted benzaldehyde, ethyl acetoacetate and ammonium acetate.