Magnetic silica/graphene oxide nanocomposite supported ionic liquid–manganese complex as a powerful catalyst for the synthesis of tetrahydrobenzopyrans

A novel magnetic silica/graphene oxide nanocomposite supported ionic liquid/manganese complex (Fe(3)O(4)@SiO(2)-NH(2)/GO/IL-Mn) is prepared, characterized and its catalytic application is investigated. The Fe(3)O(4)@SiO(2)-NH(2)/GO/IL-Mn catalyst was synthesized via chemical immobilization of graphene oxide on Fe(3)O(4)@SiO(2) nanoparticles followed by modification with ionic liquid/Mn complex. This nanocomposite was characterized by using SEM, TGA, FT-IR, PXRD, EDX, TEM, nitrogen adsorption–desorption, and VSM analyses. The catalytic application of Fe(3)O(4)@SiO(2)-NH(2)/GO/IL-Mn was studied in the synthesis of tetrahydrobenzo[b]pyrans (THBPs) in water solvent at RT. This nanocatalyst was successfully recovered and reused at least eight times without a significant decrease in its activity.