Enhanced ethyl levulinate production from citrus peels through an in-situ hydrothermal reaction

This study introduced the enhanced production of ethyl levulinate (EL) by using waste citrus peels and verified the positive roles of the moisture of the biomass in producing EL. The effects of various parameters on the EL production were investigated. The optimal conditions for EL production were reaction temperature 150 °C, acid volume 0.2 ml, co-solvent 2 ml, and ethanol 2 ml based on 0.3 g of dry biomass with a moisture content of 50 wt%. Under these conditions, the EL yield was 27.81 wt% based on a dry feedstock. This is significantly high compared to previous studies that produced EL from other cellulosic materials because the co-solvent forms a miscible phase with EL, facilitating mass transfer of the EL to the co-solvent phase to promote the forward reaction and inhibit the side reaction.