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

Commercial 65% Ni/SiO2-Al2O3 (Ni/SA) catalyst was investigated for hydrocyclisation of levulinic acid (LA) to -valerolactone (Gvl) in presence of different hydrogen sources such as molecular hydrogen, isopropyl alcohol (IPA), and formic acid. At optimized reaction condition (200 degrees C, 10bar H-2 for 30min), the Ni/SA catalyst showed 100% yield of Gvl using molecular H-2 in tetrahydrofuran (THF) medium. The catalyst also exhibited 99% yield of Gvl in IPA through catalytic transfer hydrocyclisation of LA at 200 degrees C in 15min. Further, the hydrocyclisation was successfully demonstrated in continuous mode using molecular hydrogen for 20h time-on-stream which showed 98-99% conversion of LA with 100% selectivity of Gvl at optimized reaction condition in THF medium. [GRAPHICS] .