Efficient hydrogenation of biomass-derived furfural and levulinic acid on the facilely synthesized noble-metal-free Cu-Cr catalyst

Biomass-derived platform intermediate furfural and levulinic acid were efficiently hydrogenated to the value-added furfuryl alcohol and promising biofuel gamma-valerolactone, respectively, using a noble-metal-free Cu-Cr catalyst, which was facilely and successfully synthesized by a modified co-precipitation method using the cheap metal nitrates. In the first hydrogenation of furfural, 95% yield of furfuryl alcohol was highly selectively produced at 99% conversion of furfural under the mild conditions. For the hydrogenation of levulinic acid, 90% yield of gamma-valerolactone was highly selectively produced at 97.8% conversion. Besides, the physical properties of the resulting Cu-Cr catalysts were studied by XRD (X-ray diffraction), EDX (Energy-dispersive X-ray), TEM (Transmission electron microscopy) and XPS (X-ray photoelectron spectroscopy) to reveal their influence on the catalytic performance. Subsequently, different reaction parameters were studied and it was found that Cu2+/Cr3+ ratios (0.5, 1 and 2), reaction temperature (120-220 degrees C) and hydrogen pressure (35-70 bar) presented important influence on the catalytic activities. In the end, the stability of the Cu-Cr catalysts was also studied. (C) 2013 Elsevier Ltd. All rights reserved.