Ethyl Levulinate Synthesis from Levulinic Acid and Furfuryl Alcohol by Using Modified Carbon Cryogel

Abstract

The research on ethyl levulinate synthesis is now increased due to its potential to be derived from biomass and for applications in biofuel. In the present work, model compound of biomass-derived intermediates, levulinic acid and furfural alcohol, were utilized for ethyl levulinate synthesis using modified carbon cryogel. Carbon cryogel produced from urea and furfural (UCC) mixtures was modified via sulfonation (UCC-S) and subsequently doped with Fe (UCC-S-Fe) to increase the surface chemistry of the reaction. In order to study the acidity and phase structure of the catalyst, the UCC-S and UCC-S-Fe were characterized by using NH₃-TPD and XRD. The ethanolysis of levulinic acid and furfuryl alcohol were conducted in a batch reaction system for the catalytic testing experiment by study the effect of reaction time and catalyst loading. At the selected conditions, with UCC-S as the catalyst, a high ethyl levulinate yield of 99.5 mol% was obtained from ethanolysis of levulinic acid using 10 wt% of a catalyst loading for 4 h. Although UCC-S catalyst gives low ethyl levulinate yield from ethanolysis of furfuryl alcohol, a high yield ethyl levulinate of 97.8 mol% was observed within 5 h of reaction time by applying 20 wt% of UCC-S-Fe catalyst loading. Thus, the modification of urea-furfural carbon cryogel via sulfonation and Fe-doping have improved the properties of carbon cryogel and performed as a promising solid acid catalyst for ethyl levulinate production. However, different activity performances were demonstrated by the two catalysts in the ethanolysis reactions of levulinic acid and furfuryl alcohol.