Alum [KAl(SO4)2.12H2O] is an inexpensive, efficient, non-toxic and mild catalyst for the preparation of acylals from aromatic and heteroaryl aldehydes with acetic anhydride at room temperature under solvent-free conditions. This method gives remarkable advantages such as excellent chemoselectivity, mild reaction conditions, short reaction times and excellent yields, and offers a green synthetic solution by avoiding toxic catalysts and hazardous solvents.Keywords: Alum, acylals, aromatic and heteroaryl aldehydes, solvent-free synthesis, room temperatur
