A sustainable process for the production of γ-valerolactone by hydrogenation of biomass-derived levulinic acid

Abstract

A sustainable process for the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is reported. GVL can be easily obtained in high yield, adopting very mild reaction conditions, by the hydrogenation of an aqueous solution of levulinic acid using a commercial ruthenium supported catalyst in combination with a heterogeneous acid co-catalyst, such as the ion exchange resins Amberlyst A70 or A15, niobium phosphate, or oxide. All the hydrogenations were carried out at 70–50 °C and at low hydrogen pressure (3–0.5 MPa). The most effective acid co-catalyst was the ion exchange resin Amberlyst A70, which produced a high yield of GVL (99 mol%) and an activity of 558 h⁻¹ after 3 h of reaction, whilst working at 0.5 MPa of hydrogen and 70 °C. The combined effect of acid and hydrogenating heterogeneous components was also verified for the hydrogenation of aliphatic ketones to the corresponding alcohols, thus opening a new perspective for this process.