Nano-sized clinoptilolite as a green catalyst for the rapid and chemoselective N-formylation of amines

An ultrasound-assisted, simple, fast and efficient method reported for the chemoselective N-formylation of amines with formic acid in the presence of nanozeolite clinoptilolite (nano-CP) under solvent-free reaction conditions to give the corresponding formamides. The ultrasound increased the rate of the reaction and afforded excellent yields at room temperature. This method has the advantages of high yields, mild conditions, simple methodology, easy work up and short reaction times. The catalyst was characterized by different techniques, was recovered and reused several times without the significant loss of its catalytic performance. Graphic abstract