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

Abstract

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 ?, 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 H-2. In addition, Lewis and Bronsted 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.