Chemical valorisation of biomass derived furanics and carboxylic acids over niobium-based catalysts

Abstract

Furfural is an industrial renewable platform chemical, which can be converted to useful furanics such as -angelica lactone, carboxylic acids such as levulinic acid and valeric acid, or to higher carbon content via condensation routes for producing drop-in fuel replacements and chemicals with diverse applications. These important conversion processes may be carried out in selective fashions, albeit require adequate catalysts. They were successfully carried out using versatile, stable silica-wrapped niobium oxide nanostructured catalysts. For example, -angelica lactone was converted in an integrated fashion to ethyl levulinate in 90 % yield, and the esterification of levulinic and valeric acids gave ethyl levulinate in quantitative yield and ethyl valerate in 90 % yield, respectively, at 140 °C. Catalytic, mechanistic and kinetic modelling studies shed light into the influence of the material properties on the catalytic performances. These catalysts outperformed pure Nb2O5, as well as hydrothermally synthesized composite consisting of Nb2O5 nanoparticles embedded in a mesoporous siliceous matrix.