Effect of hydrogen donor on liquid phase catalytic transfer hydrogenation of furfural over a Ru/RuO2/C catalyst

• Catalytic transfer hydrogenation of furfural toward methyl furan was demonstrated.
• Secondary alcohols are more effective among a range of hydrogen donors.
• An optimum methyl furan yield of 76% was achieved using 2-butanol and 2-pentanol.
• Methyl furan yield increases with increasing alcohol dehydrogenation activity.
• Methyl furan yield increases with decreasing alcohol polarity.

The effect of alcohol hydrogen donor on methyl furan production through catalytic transfer hydrogenation of furfural in the liquid phase has been investigated over a mildly calcined Ru/C catalyst in the temperature range of 110–200 °C. It has been found that several parameters contribute to furfural hydrogenolysis, including alcohol dehydrogenation activity, solvent properties, as well as side reactions such as etherification between the intermediate, furfuryl alcohol, and the hydrogen donor. Methyl furan yield increases from 0 to 68% at 180 °C following the order of 2-methyl-2-butanol < tert-butanol < ethanol < 1-propanol ∼ 1-butanol < 2-propanol < 2-butanol ∼ 2-pentanol, which correlates well with the alcohol dehydrogenation activity. In ethanol, 1-propanol, 2-propanol and 2-pentanol, furfuryl alcohol hydrogenolysis to methyl furan is significantly retarded at low temperatures due to furfuryl alcohol etherification with the corresponding alcohol solvent. We find that methyl furan yield decreases with increasing alcohol polarity. An optimum methyl furan yield of 76% is attained after 10 h of reaction at 180 °C, using 2-butanol and 2-pentanol as hydrogen donors. This is the highest reported yield in the liquid phase at temperatures below 200 °C.

Methyl furan yield increases with increasing the alcohol dehydrogenation activity.Figure optionsDownload high-quality image (82 K)Download as PowerPoint slide