Ethyl levulinate synthesis from biomass derivative chemicals using iron doped sulfonated carbon cryogel catalyst

Abstract

Biomass-derived intermediate chemicals, such as furfuryl alcohol (FA) and levulinic acid (LA) are feeds for ethanolysis reaction to produce ethyl levulinate (EL). EL is a promising chemical that can be used as a biofuel additive and precursor for chemical synthesis, such as γ-valerolactone. The present study conducted the ethanolysis of FA and LA using modified carbon cryogel as heterogeneous catalysts for improving the EL yield. The carbon cryogel (UCC) precursor was produced from urea and furfural, and modified via sulfonation. Iron (Fe) doping was then conducted to improve the surface chemistry of the catalyst. The catalytic activity of sulfonated carbon cryogel (UCC-S) was evaluated for LA ethanolysis, and the UCC-S-Fe prepared from the incorporation of Fe on UCC-S was utilised to catalyse FA ethanolysis. The effects of reaction parameters (i.e., time, molar ratio of ethanol to feed, catalyst loading, and reaction temperature) were significant on the catalytic performance. High EL yield of 95.8 mol% and 95.4 mol% were obtained from the ethanolysis of LA and FA, respectively. The performance of ethanolysis of carbohydrates and various biomass samples was evaluated to determine the EL yield using UCC-S-Fe. Both UCC-S and UCC-S-Fe were characterised using FTIR, XRD, TGA, NH3-TPD, BET, and SEM-EDX. The modification of UCC via sulfonation and Fe-doping improved the catalyst properties, and UCC-S-Fe demonstrated the potential to enhance biomass conversion to EL.