InSitu Catalytic Hydrogenation of Biomass-Derived Methyl Levulinate to -Valerolactone in Methanol

In this work, the hydrocyclization of methyl levulinate (ML) to -valerolactone (GVL) was performed in MeOH over an insitu prepared nanocopper catalyst without external H-2. This nanocopper catalyst served as a dual-functional catalyst for both hydrogen production by MeOH reforming and hydrogenation of ML. Nearly quantitative ML conversion with a GVL selectivity of 87.6% was achieved at 240 degrees C in 1h in MeOH under a nitrogen atmosphere. ML in the methanolysis products of cellulose also could be hydrogenated effectively to GVL over this nanocopper catalyst even in the presence of humins to give an ML conversion of 94.1% and a GVL selectivity of 73.2% at 240 degrees C in 4h. The absorption behavior of humins on the surface of the nanocopper catalyst was observed, which resulted in a pronounced increase in the acidic sites of the nanocopper catalyst that facilitate ring-opening and the hydrocarboxylation/alkoxycarbonylation of GVL to byproducts.