Sulfonic acid-functionalized silica-coated magnetic Fe3O4 nanoparticles were synthesized and applied as a green catalyst for an efficient and environmentally friendly ring opening of epoxides with aromatic amines in good to excellent yields with high chemoselectivity. Clean aminolysis of various aliphatic and aromatic epoxides in ethanol generates beta-hydroxyamines under mild reaction conditions. The synthesized acidic magnetic nanoparticles were recovered using a simple external magnet and successfully reused for five runs without any appreciable loss of catalytic activity. Copyright (C) 2016 John Wiley & Sons, Ltd.