(617ef) Selective Electrocatalytic Hydrogenation of Furfural on Metal Electrodes

Electrocatalytic hydrogenation of biomass-derived compounds is an emerging route for biofuel and chemical production [1â??3]. Furfural is a dehydration product of xylose that can serve as a building block for many biorenewable fuels and chemicals including valuable reduction products furfuryl alcohol and 2-methylfuran. Furfuryl alcohol has served as a precursor for various synthetic fibers, rubbers, resins and other chemicals, while 2-methylfuran is a good candidate to replace popular biofuels such as ethanol because of its higher heating value and higher octane number. Reduction of furfural is mainly obtained through heterogeneous vapor phase catalytic reactions. However, such routes typically require precious metal catalysts, high pressure external hydrogen gas and relatively high temperatures which increase operation costs. The electrocatalytic process is an alternative route, which can be driven by renewable electricity sources, does not require external hydrogen, and can be performed at ambient conditions [1â??2].

In this talk, the electrocatalytic hydrogenation of furfural in acidic aqueous solutions on metal foil electrodes will be presented. Among all the metals tested, copper was unique toward 2-methylfuran production with high selectivity and electron efficiency. Other metals generated mainly furfuryl alcohol or products of dimerization reactions, or suffered from low electron efficiency resulting from the competing hydrogen evolution reaction. With an emphasis on copper, the effects of applied electrode potential, electrolyte composition and pH, and other reaction conditions on the efficiency and selectivity of furfural conversion were studied. For example, 2-methylfuran selectivity increased with decreasing pH and increasing electrode potentials. Dimerization products were majorly formed at conditions of higher pH and greater initial furfural concentrations. Cyclic voltammetry and bulk electrolysis studies elucidated the reaction pathways for formation of 2-methylfuran and furfuryl alcohol on copper electrodes. This work opens up opportunities to use earth-abundant materials and mild reaction conditions for efficient conversion of biorenewable chemicals.

1. Nilges, P. and U. Schroder, Electrochemistry for biofuel generation: production of furans by electrocatalytic hydrogenation of furfurals. Energy & Environmental Science, 2013. 6, 2925.

2. Xin, L., et al., Electricity storage in biofuels: selective electrocatalytic reduction of levulinic acid to valeric acid or gamma-valerolactone. ChemSusChem, 2013. 6, 674.

3. Green, S.K., et al., The electrocatalytic hydrogenation of furanic compounds in a continuous electrocatalytic membrane reactor. Green Chemistry, 2013. 15, 1869.