C=C Bond Hydrogenation vs C-O Bond Hydrogenolysis of Furfuryl Alcohol on Ru: A DFT Study

Periodic density functional theory (DFT) simulations were used to thoroughly study the complete reaction network for the hydrogenation and hydrogenolysis of furfuryl alcohol (FA) on the Ru (0001) surface. The reaction pathways for the formation of tetrahydrofurfuryl alcohol (THFA), 1,2-pentanediol (1,2-PeD), 1,5-pentanediol (1,5-PeD), and 2-methyl furan (2-MF) from FA were established. In the most stable configuration, the FA ring was adsorbed parallel to the surface and centered over a hollow site with a binding energy of -180 kJ/mol. Hydrogenation of the FA ring was found to be the kinetically facile pathway for the formation of THFA. The byproducts 1,2-PeD and 1,5-PeD could be attributed to the outstanding C-ring-O bond cleavage ability of the Ru metal. However, high activation barriers for further hydrogenation of the ring-opened products and alkyl C-O bond cleavage kinetically limited the formation of 1,2-PeD, 1,5-PeD, and 2-MF on Ru surface during the vapor-phase hydrodeoxygenation of FA.