Facile synthesis of furfuryl ethyl ether in high yield via the reductive etherification of furfural in ethanol over Pd/C under mild conditions

Abstract

The one-pot synthesis of furfuryl ethyl ether (FEE) over Pd nanoparticles supported on TiO₂, Al₂O₃, SiO₂, and active carbon via the catalytic reductive etherification of furfural in ethanol was systematically studied. The Pd nanoparticles supported on SiO₂, TiO₂ and active carbon are all active for this novel process under mild reaction conditions, with Pd/C showing the highest selectivity to FEE. The effects of palladium loading, reaction temperature, and hydrogen pressure on the activity and selectivity of Pd/C have been investigated in detail. The results demonstrate that suitable Pd amount, low reaction temperature of about 60 °C, and low H₂ pressure of about 0.3 MPa are favorable for the formation of the desired ether product. Under the optimized conditions, an unprecedented high yield of up to 81% of FEE was firstly obtained with the major by-products being furfuryl alcohol and 2-methyltetrahydrofuran. Compared with the conventional hydrogenation-etherification route via furfural alcohol as a reaction intermediate, the reductive etherification shows significant advantage in product yield because of its much lower reaction temperature that is required.