Conversion of furfuryl alcohol into alkyl‒levulinates using solid acid catalysts

Alkyl levulinates (alkyl‒LA) are biomass derived, versatile chemicals for flavours, chemical solvents and fuel additives. In this work, we used furfuryl alcohol (FFA) to synthesise alkyl‒LA and systematically investigated the FFA alcoholysis using batch and continuous reactors . We screened various solid acid catalysts in the batch reactor system and found that Amberlyst‒15 resin performed best, not only showing high levels of alkyl‒LA yields, but also suppressing the amount of undesired dialkyl ether. We observed two plausible intermediates (alkoxy‒methylfuran and tri-alkoxy-pentanone) during the FFA alcoholysis. In the continuous reactor system, the water content in the reaction mixture influenced the conversion of FFA as well as the yield of alkyl‒LA, providing additional reaction pathways (e.g., ring opening of FFA). For the first time, we demonstrated a branched C8 alcohol (2‒ethyl‒1‒hexanol, ethylhexanol) can be used to obtain the corresponding levulinate (2‒ethyl‒1‒hexyl‒LA, ethylhexyl‒LA). With the optimised reaction conditions, we could obtain ethylhexyl‒LA with the yield of 83% and 98% in the batch and continuous reactor system, respectively.