A Cu-BTC metal–organic framework (MOF) as an efficient heterogeneous catalyst for the aerobic oxidative synthesis of imines from primary amines under solvent free conditions

Abstract

A Cu-BTC (MOF-199) [copper(II)-benzene-1,3,5-tricarboxylate] catalyst has been synthesized and evaluated for imine synthesis from amine compounds under neat conditions. The performance of the Cu-BTC MOF was significantly higher than that of the CuO supported on Al₂O₃, TiO₂ and SiO₂ catalysts. The role of surface Lewis acid sites on the catalyst in the formation of imine products was illustrated by the pyridine-IR studies. The recovered Cu-BTC catalyst demonstrated consistent activity for five cycles under similar experimental conditions. The physicochemical properties of the catalysts were analyzed by XRD, BET-SA, FT-IR, UV-DRS, SEM, TEM, XPS and pyridine adsorbed DRIFT spectroscopy.