Efficient Oxidative Transformation of Furfural into Succinic Acid over Acidic Metal-Free Graphene Oxide

Graphene oxide (GO), prepared by the modified Hummers method, was applied as a highly active and selective solid acid catalyst for oxidative transformation of furfural (FAL) into succinic acid (SA) with H2O2 as the oxidant. Over a GO catalyst, 88.2% yield of SA from FAL was achieved under relatively mild reaction conditions. By characterization of the prepared GO and various control experiments, the higher efficiency of GO than conventional catalysts was attributed to its unique atomic layered structure and suitable acidity. On the basis of the results in this work and previous reports, a reasonable reaction pathway was proposed. Different from other acid catalysts, it was suggested that the aromatic rings in GO and the edges decorated with -SO3H groups worked synergistically in FAL oxidation. The GO catalyst was found reusable, and only a slight decrease in the catalytic activity was observed after six cycles.