Catalysis and reaction mechanisms of N-formylation of amines using Fe(III)-exchanged sepiolite

This study presents a rapid, economical and “green” N-formylation of anilines with formic acid (FA) using Fe(III)-exchanged sepiolite (IES) as a catalyst. The IES exhibited excellent catalytic properties and the reactions were complete within 20.90 min to afford products with high yields. The adsorption mechanism of FA on the IES sample was studied by infrared (IR) spectroscopy at a temperature range of 120–400°C. The thermal desorption of pyridine was detected by the IR technique to estimate the acidity of IES. Lewis acid-bound pyridine bands at 1618–1631 cm^-1 and 1443–1445 cm^-1 were observed even after the IES sample was heated above 400°C.