Magnetically nano Fe 3 O 4 efficiently catalyzes solvent-free conversion of various carbonyl compounds to the corresponding oximes with NH 2 OH·HCl. The reactions were carried out in oil bath (70°C to 80°C) at solvent-free conditions to afford oximes in high to excellent yields. This method offers some advantages in terms of clean reaction conditions, recyclable of catalyst, short reaction times, easy work-up procedure, and suppression of side products.

Nano-<em>Fe₃O₄</em> particles were used as a green and heterogeneous catalyst for Beckmann rearrangement under ultrasound irradiation and protic solvent condition in excellent yields. The advantage of this method was simple, inexpensive, easy work-up procedure, suppression of any side product.

Aldehydes compounds selective converted to 1,1-diacetates as protective reagent with SiO 2 @FeSO 4 nano composite as effective nano catalyst at room temperature under solvent-free condition and acetic anhydride (Ac 2 O) as acetylation reagent. This method provides several advantages, such as low cost of the nano catalyst, high yields, short reaction time, chemoselective protection of aldehydes and operational simplicity. Aromatic and aliphatic, simple and conjugated aldehydes were protected with excellent yields. In addition, chemoselective reductive acetylation of aldehydes over ketones was achieved perfectly with the reagent at room temperature.