High efficient conversion of furfural to 2-methylfuran over Ni-Cu/Al2O3 catalyst with formic acid as a hydrogen donor

Conversion of furfural to 2-methylfuran over Cu/Al₂O₃, Ni/Al₂O₃ and Ni-Cu/Al₂O₃ catalysts were investigated with formic acid as a hydrogen donor. Ni/Al₂O₃ showed a high catalytic activity but a moderate selectivity to 2-methylfuran. Contrarily, Cu/Al₂O₃ showed a low catalytic activity but a high selectivity for carbonyl reduction. Over the bimetallic catalysts Ni-10%Cu/Al₂O₃, by increasing Ni content, more furfural was converted with the reduction of carbonyl primarily. The effect of reaction solvent and the fraction of formic acid were also studied. The result showed that isopropanol solvent could contribute to the formation of furfuryl alcohol with 96% selectivity through the transfer hydrogenation process. Formic acid could decompose to H₂ and CO₂, remarkably promoting the hydrogenolysis of furfuryl alcohol to 2-methylfuran. Finally, 100% conversion and 92 mol% yield of 2-methylfuran could be obtained over 10%Ni-10%Cu/Al₂O₃. It was attributed to the synergic effect of Ni-Cu metals, with increased affinity for carbonyl reduction.