Nano-silica supported ethane-sulfonic acid: An efficient heterogeneous solid acid catalyst for one-pot synthesis of xanthene and acridine derivatives

In this study, silica nanoparticles were used as support to prepare a new heterogeneous catalyst system for application in organic reactions. The reaction of silica nanoparticles with sodium 2-bromoethane-1-sulfonate resulted in the connection of a sulfonic acid group on the surface of silica nanoparticles (NSESA). The synthetic catalyst system was characterized using different microscopic and spectroscopic techniques. After characterization of NSESA, its catalytic activity was evaluated in a multicomponent reaction for one-pot synthesis of xanthene and acridine derivatives. Results of this study show that this catalyst system is effective in this reaction so that a range of xanthenes and acridines were obtained in high isolated yields under optimized conditions. The catalyst system was reusable at least for 7 times without significant decreasing in its catalytic activity.