Synthesis of ethyl levulinate from furfuryl alcohol using waste yeast/sulfonic acid heterogeneous catalyst system

In this study, a functionalized, heterogeneous, and insoluble acid catalyst of yeast-sulfonic acid was prepared by simple steps using spent yeast and sulfonic acid as raw materials. Its unique internal microstructure and abundant sulfonic acid groups on the surface endow it with the properties of Brønsted acid and high-performance activity. The catalyst was characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Barrett–Emmett–Teller N 2 adsorption–desorption analysis, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The catalyzed synthesis of ethyl levulinate (EL) from furfuryl alcohol (FA) was carried out at a temperature of 120 °C for 2 h. The conversion rate and yield percentages for the catalyzed reaction of FA to produce EL were 98.2 and 94.7%, respectively. The results show that the amount of catalyst used and reaction conditions significantly impacted the EL yield and FA conversion rate. Overall, the possible reaction mechanism for the conversion of FA to EL was proposed. It was found that the main reason for the high catalytic activity of the catalyst was the effect of Brønsted acid sites.