A green method for solvent-free conversion of epoxides to thiiranes using NH4SCN in the presence of NiFe2O4 and MgFe2O4 magnetic nanocatalysts

Nickel and magnesium ferrite magnetic nanoparticles were fabricated and applied as efficient and reusable catalysts in the solvent-free conversion of various epoxides to the corresponding thiiranes with ammonium thiocyanate under oil bath (60°C) conditions. NiFe₂O₄ and MgFe₂O₄ nanoparticles can catalyze the reactions at short times in high to excellent yields. The catalysts can also be recovered easily using an external magnetic field and be reused four times without any significant loss of activity.