SBA-15 obtained from rice husk ashes wet-impregnated with metals (Al, Co, Ni) as efficient catalysts for 1,4-dihydropyridine three-component reaction

We report the preparation and full characterization of Al, Co and Ni-SBA-15 materials that were easily prepared from rice-industry wastes as a silicon source, followed by the impregnation of metal salts. The materials were successfully employed as heterogeneous catalysts for the 1,4-dihydropyridine multicomponent synthesis in ethanol as the solvent. They featured a number of advantages, such as low metal load due to mesoporous catalytic sites (4 nm), low reaction times, high yields and simple catalyst isolation and purification process, which resulted in high efficiency and low environmental impact. Al-SBA-15 showed weaker Lewis acid sites and the best performance as a catalyst, affording higher product conversion (>80% in 10 minutes) and higher TOF values.

Automated summary

In this study, Al, Co, and Ni-SBA-15 materials were prepared from rice-industry wastes as a silicon source and used as catalysts for the 1,4-dihydropyridine multicomponent synthesis in ethanol. These materials exhibited advantages such as low metal load, short reaction times, high yields, and a simple catalyst isolation and purification process, resulting in high efficiency and low environmental impact. Among them, Al-SBA-15 showed weaker Lewis acid sites and performed the best, achieving higher product conversion and TOF values.