Screening of Solvents, Hydrogen Source, and Investigation of Reaction Mechanism for the Hydrocyclisation of Levulinic Acid to γ-Valerolactone Using Ni/SiO2–Al2O3 Catalyst

Abstract

Commercial 65% Ni/SiO2–Al2O3 (Ni/SA) catalyst was investigated for hydrocyclisation of levulinic acid (LA) to γ-valerolactone (Gvl) in presence of different hydrogen sources such as molecular hydrogen, isopropyl alcohol (IPA), and formic acid. At optimized reaction condition (200 °C, 10 bar H2 for 30 min), the Ni/SA catalyst showed 100% yield of Gvl using molecular H2 in tetrahydrofuran (THF) medium. The catalyst also exhibited 99% yield of Gvl in IPA through catalytic transfer hydrocyclisation of LA at 200 °C in 15 min. Further, the hydrocyclisation was successfully demonstrated in continuous mode using molecular hydrogen for 20 h time-on-stream which showed 98–99% conversion of LA with 100% selectivity of Gvl at optimized reaction condition in THF medium.