Continuous Flow Selective Hydrogenation of 5-Hydroxymethylfurfural to 2,5-Dimethylfuran Using Highly Active and Stable Cu–Pd/Reduced Graphene Oxide

2,5-Dimethylfuran (DMF) has been considered a promising biofuel additive, potentially derived from renewable resources. There have been various reports on DMF production from hydrogenation of 5-hydroxymethylfurfural (HMF). However, most reports employed high hydrogen pressure, long reaction times, and reactions under batch conditions. In this study, Cu–Pd bimetallic catalysts incorporated on reduced graphene oxide (RGO) were used for selective hydrogenation of HMF to DMF using 2-propanol as hydrogen donor under continuous flow conditions. Synthesized catalysts were characterized by N2 physisorption, SEM-EDX, XRD, XPS, TEM, and H2-TPR techniques. 10Cu-1Pd/RGO exhibited 96% HMF conversion with 95% DMF yield under optimum reaction conditions with good stability with time on stream. XRD and XPS results pointed to the presence of a palladium–copper alloy, which could enhance both the activity and especially the stability in the conversion of HMF toward DMF. The effect of temperature, pressure, and feed flow rate were also investigated on the catalytic performance. The stability of catalyst was tested for 8 h time on stream, where it was found that the catalyst displayed good stability.