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 (FeO@SiO-NH/GO/IL-Mn) is prepared, characterized and its catalytic application is investigated. The FeO@SiO-NH/GO/IL-Mn catalyst was synthesized via chemical immobilization of graphene oxide on FeO@SiO 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 FeO@SiO-NH/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.