Catalytic Conversion of Ethyl Levulinate to γ-Valerolactone Under Mild Conditions over Zr-Beta Acidic Zeolite Prepared by Hydrothermal Method

Abstract

As an important biomass resource, γ-valerolactone (GVL) shows considerable potential for applications in biofuel production, organic synthesis, polymer, and food industries. Herein, an effective method was presented for synthesizing GVL through the catalytic transfer hydrogenation (CTH) of ethyl levulinate (EL) under mild conditions. Using isopropanol as a hydrogen donor, a 100% conversion of ethyl levulinate and an 88.7% yield of GVL were achieved over 2%Zr-Beta-7d catalyst at 110 °C for 8 h. The acidic sites of synthesized Zr-Beta via hydrothermal methods easily adjusted and offered high catalytic activity and selectivity. The Lewis (L) acid sites on the zeolite serve as the active centers for the conversion of EL. Characterization results indicate that the amounts of L acid sites on Zr-Beta increased with the Zr content and crystallization time rose, thus enhancing the selectivity for GVL. Additionally, the influences of catalyst dosage, reaction temperature, and time on catalytic performance are studied, as well as calculations of kinetic parameters such as reaction rate constants and activation energies. The 2%Zr-Beta-7d catalyst retains its high performance after five cycles. The current research may present an efficient approach for the conversion of EL to GVL under mild conditions.