The Role of the Hydrogen Source on the Selective Production of γ-Valerolactone and 2-Methyltetrahydrofuran from Levulinic Acid.

A mechanistic study of the hydrogenation reaction of levulinic acid (LA) to 2-methyltetrahydrofuyran (MTHF) was performed using three different solvents under reactive H2 and inert N2 atmospheres. Under the applied reaction conditions, catalytic transfer hydrogenation and hydrogenation with molecular H2 were effective at producing high yields of γ-valerolactone. However, the conversion of this stable intermediate to MTHF required the combination of both hydrogen sources (the solvent and the H2 atmosphere) to achieve good yields. The reaction system with 2-propanol as solvent and Ni-Cu/Al2 O3 as catalyst allowed full conversion of LA and a MTHF yield of 80 % after 20 h reaction time at 250 °C and 40 bar of H2 (at room temperature). The system showed the same catalytic activity at LA feed concentrations of 5 and up to 30 wt%, and also when high acetone concentration at the beginning of the reaction were added, which confirmed the potential industrial applications of this solvent/catalyst system.