PERTANIKA JOURNAL OF SCIENCE AND TECHNOLOGY

Levulinate esters are promising value-added energy chemicals that have piqued researchers’ worldwide interest owing to their potential as fuel additives. The reactions mainly concentrate on catalytic performance and offer limited research on the use of biomass-derived solid catalysts. This study investigated the efficiency of palm waste-derived magnetic solid catalysts and optimised the esterification process to improve ethyl levulinate yield. The results showed that the sulfonic group, SO₃H, provides strong Brønsted acid sites for esterification, while ferric ions, Fe³⁺, act as Lewis acids to enhance carbonyl activation, jointly catalysing the conversion to ethyl levulinate. The ethyl levulinate yield reached 87.0 mol%, achieved with an EFB fibre/γ-Fe₂O₃ catalyst (9.1 wt%) and an ethanol-to-levulinic acid molar ratio of 13.6:1 at 66.7 °C for 6 h. FT-IR and GC-FID analyses validated the formation of the ester groups following the esterification reaction. The catalyst can be easily removed with an external magnet, offering an effective way to use solid catalysts in esterification.