Towards Production of γ-valerolactone via Hydrogenation of Aqueous Levulinic Acid

Abstract : Synthesis of GVL (γ-valerolactone) via hydrogenation of aqueous LA (levulinic acid) with H2 over heterogeneous catalyst (Ru/C) was investigated. In the first part, a study of the influence of various operating conditions was conducted including that of temperature (90–180°C), stirring rate (500–1200 rpm), catalyst loading (0.1–2.0 g), hydrogen pressure (0.4–2.8 MPa) and initial LA concentration (0.5–2 M). In the second part, influence of supercritical CO2 (scCO2) on hydrogenation rate and GVL yield were investigated. Hydrogenation of aqueous LA under scCO2 and under N2 atmosphere was carried out in batch reactor at 150°C and was compared with the case when no additional gases were present. The result indicated that the use of scCO2 had no beneficial effect neither in terms of LA conversion nor hydrogenation rate when the amount of hydrogen was relatively low compared to the stoichiometry. This effect was mitigated when more hydrogen was present.