ZrO2/SBA-15 as an efficient catalyst for the production of γ-valerolactone from biomass-derived levulinic acid in the vapour phase at atmospheric pressure
γ-Valerolactone is a promising renewable feedstock for the production of fuels and industrial chemicals. In this work, SBA-15 supported ZrO2 catalysts prepared by a wet impregnation method with various ZrO2 loadings ranging from 10 to 30 weight% have been studied for the production of γ-valerolactone from levulinic acid via catalytic transfer hydrogenation and cyclization with isopropanol as a H-donor in the vapour phase at atmospheric pressure. Among the catalysts, 25 weight% ZrO2/SBA-15 has been identified as an efficient catalyst for the transfer hydrogenation, delivering 100% conversion of levulinic acid with 93% selectivity towards γ-valerolactone. The physicochemical characteristics of these catalysts were achieved by X-ray diffraction, BET surface area, pore size distribution, UV-visible spectroscopy, temperature-programmed desorption of ammonia, SEM, TEM and ICP-OES techniques. The characterization studies divulge the presence of ZrO2 with well-dispersed acidic sites, enhanced surface area, and ease of accessibility for the active sites within the uniform pore channels, and these engendered the excellent catalytic performance with low molar ratios 1 : 7 (levulinic acid : isopropanol). Moreover, the catalyst showed sturdiness during 20 hours on-stream study.