Upgrading of aqueous ethanol to fuel grade higher alcohols over dandelion-like Ni-Sn catalyst

Higher alcohols are increasingly attracting attention as transportation fuel additives due to the advantages over bioethanol that include higher heat value, less hygroscopic nature, and reduced-engine problems. Typically, bioethanol is produced as diluted aqueous solution from biomass fermentation, thus the direct upgrading of aqueous ethanol is favorable to avoid the costly isolation process. Here, the direct upgrading of aqueous ethanol to higher alcohols was successfully achieved by using the non-precious dandelion-like NiSnH catalysts under mild hydrothermal conditions, which exhibited a comparable catalytic activity with Pd/C catalyst. Spontaneous phase-separable higher alcohol product was obtained, the C4+ higher alcohol selectivity reached 91.6% with iso-/n- ratio of 0.83 in the liquid products, which makes it suitable to be directly used as fuel additives. The promotion role of Ni-Sn catalyst on the production of higher alcohols and possible reaction pathway were also discussed.