Nano-Fe3O4-encapsulated silica particles bearing sulfonic acid groups as a magnetically separable catalyst for green synthesis of 1,1-diacetates

Sulfonic acid-functionalized silica-coated nano-Fe(3)O(4)particles (Fe3O4@SiO2-SO3H) serve as a novel heterogeneous catalyst for the synthesis of acylals by direct condensation of aldehydes with acetic anhydride under solvent-free conditions at room temperature in short reaction times and excellent yields. The catalyst could be easily separated from the final product using an external magnet and reused several times without consequential loss of reactivity.