A highly efficient, green and expeditious solvent-free method is described for the chemoselective conversion of aldehydes to the corresponding acylals in excellent yields, using acetic anhydride in the presence of catalytic amount (20 mol%) of silica-supported LiHSO4. Ketones does not react under these reaction conditions. LiHSO4/SiO2 can be recovered and reused without any significant loss of its catalytic activity.