One-pot, cascade conversion of cellulose to γ-valerolactone over a multifunctional Ru–Cu/zeolite-Y catalyst in supercritical methanol

A one-pot cascade conversion of cellulose to GVL was investigated over bimetallic Ru–Cu deposited on a zeolite Y (Ru–Cu/Z) catalyst. Under supercritical methanol conditions, high-yield (49.8%) cascade conversion of cellulose to GVL was achieved at 250 °C, with an initial H₂ pressure of 3.0 MPa and reaction time of 5 h. The Ru–Cu/Z catalyst was synthesized using activated reductive deposition (ARD), which resulted in the selective deposition of Cu nanodomains on Ru nanoparticles, thereby facilitating the dissociative adsorption of H₂. In addition, Lewis and Brønsted acid sites of Cu-doped zeolite Y effectively proceeded to cascade conversion reactions, including alcoholysis, isomerization, dehydration, and acetalization reactions, suppressing humin formation. The bimetallic Ru–Cu/Z catalyst was used in six consecutive runs, with a marginal loss of activity. The structure–performance relationships of the Ru–Cu/Z catalysts synthesized using ARD, incipient wet impregnation, and reduction deposition methods were compared.