Furfural Valorization to γ-Valerolactone over Zr/Sn Zeolite-Supported Catalysts in a Liquid-Phase Continuous Flow Reactor

This work presents for the first time the combined effect of Sn and Zr in the conversion of furfural (FU) to γ-valerolactone (GVL) by using a single liquid-phase continuous flow reactor. To address the high costs and environmental impact of this cascade reaction, catalytic transfer hydrogenation is a promising approach, utilizing alcohols as hydrogen donors in place of molecular H2. This process, which requires both Lewis and Bro̷nsted acidity, when coupled with heterogeneous catalysts, offers a potentially more cost-effective and environmentally friendly alternative. The production of GVL in one pot has been studied using Sn- and Zr-based catalysts supported on dealuminated zeolite Y. The bimetallic catalyst with a Sn:Zr at. ratio of 1:1 achieved the best performance, reaching a yield to GVL of ca. 45% at 180 °C using 2-propanol as a hydrogen source, with a 10 min contact time. Moreover, stability studies, including long-term catalytic tests under reaction conditions, were carried out to evaluate the durability and the deactivation. In addition, an efficient regeneration protocol was developed and optimized, enabling catalyst reuse across multiple cycles with performance in terms of conversion and selectivities comparable to those observed with the fresh materials.