Microwave-assisted reduction of levulinic acid with alcohols producing γ-valerolactone in the presence of a Ru/C catalyst

• Ru catalyses reduction of levulinic acid with secondary alcohols to γ-valerolactone.
• Reaction rate increases under microwave irradiation compared to conventional heating.
• i-Propanol and 2-butanol are the best reductants for levulinic acid and its esters.
• The dehydrogenation–hydrogenation mechanism with Ru0 active species was proposed.
• Ru/C exhibited stability upon recycling.

γ-Valerolactone can be synthesized by reduction of levulinic acid and its esters in the presence of secondary alcohols as hydrogen donors and Ru/C as catalyst. The reaction rate increases when using microwave heating. Quantitative formation of γ-valerolactone was observed within 25 min at 160 °C under microwave heating based on levulinic acid and i-propanol. The reaction appears to proceed via a dehydrogenation–hydrogenation sequence.

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