Furfural hydrogenation over Cu, Ni, Pd, Pt, Re, Rh and Ru catalysts: Ab initio modelling of adsorption, desorption and reaction micro-kinetics

Hydrogenation, hydrodeoxygenation and ring opening of biomass-derived furfural were studied by using Pd/C, Pt/C, Re/C, Ru/C, Rh/C, Ni/C and Cu/C catalysts. Based on experiments, a generalized micro-kinetic model was developed, describing kinetics of tested catalysts well. Pd/C could unselectively hydrogenate furfural's ring, aldehyde group or both and was the most active tested catalyst. Selective aldehyde group hydrogenation, followed by deoxygenation was observed with other catalysts. This route was also favorable thermodynamically according to density functional theory (DFT) calculations. Only Ru/C could form methyltetrahydrofuran (45.3 % yield) and ring opening products at 200 degrees C. Reaction conditions were optimized in silico for most promising catalysts (Pd, Pt, Re, Ni on carbon), by fixing the kinetic parameters obtained by regression analysis and subsequently maximizing the objective function, i.e. the yield of the product of interest. Validation experiments confirmed a high Pd/C hydrogenation activity already at 40 degrees C, forming predominantly tetrahydrofurfural (85 % yield), while 95 % yield of 2-methyltetrahydrofuran was obtained by using a cheap Ni/C at 212 degrees C.