Conversion of Levulinic Acid to n-Butyl Levulinate over Mesoporous Zirconium Phosphate Catalysts

In this study, mesoporous zirconium phosphates (m-ZrPs) with a different molar ratio of phosphate to zirconium were synthesized and used as the heterogeneous catalyst for the production of n-butyl levulinate from levulinic acid. The catalysts were characterized using various techniques such as N2 adsorption-desorption, XRD, FT-IR, ICP-OES, SEM and TEM. The prepared catalysts were confirmed to possess the mesoporous structure with a high surface area. Among the synthesized catalysts, m-ZrP-2 showed the best performance in the conversion of levulinic acid to n-butyl levulinate. The reaction conditions were optimized on parameters such as reaction time, temperature, amount of catalyst, and the molar ratio of LA to n-butanol. Temperature 120 °C, reaction time 7 h, the ratio of acid to alcohol 1:9 and 0.01 g catalyst were selected as the optimum conditions. In addition, the selected m-ZrP-2 catalyst was successfully recycled for six consecutive cycles without significant loss in its activity.