A convenient and efficient protocol for the synthesis of acylals catalyzed by Brønsted acidic ionic liquids under ultrasonic irradiation.

The synthesis of acylals (1,1-diacetates) via the reactions of aldehydes with acetic anhydride was carried out in 85-97% yields at room temperature under ultrasound irradiation catalyzed by the Brønsted acidic ionic liquid [bmpy]HSO(4). This method provides several advantages, such as solvent-free conditions, operational simplicity, higher yields, and reduced environmental consequences. The ionic liquid was recovered and reused.