One-pot conversion of furfural to alkyl levulinate over bifunctional Au-H4SiW12O40/ZrO2 without external H2

Abstract

Alkyl levulinate (AL) is an important biofuel additive and precursor for the synthesis of valuable γ-valerolactone. Conventionally, it is produced by furfural hydrogenation with pressured H₂, followed by alcoholysis of the formed furfuryl alcohol (FAL). This work provides a novel strategy for the high-yield synthesis of AL via one-pot conversion of furfural with an alcohol over a metal-acid bi-functional catalyst without an external source of hydrogen. Furfural proceeded to transfer hydrogenation reaction using the alcohol as a H-donor over metal species, and then the formed FAL underwent acid-catalyzed alcoholysis to yield AL. The yield of AL reached 80.2% in the conversion of furfural with 2-propanol over Au-H₄SiW₁₂O₄₀/ZrO₂ under mild conditions. Additionally, the catalyst characterization, reaction pathway, and reusability were well presented.