Optimization of Levulinic Acid Production from Depithed Sugarcane Bagasse in 1- Ethyl-3-methylimidazolium hydrogen sulfate [EMim][HSO 4 ]

In the present study, optimal reaction conditions to produce levulinic acid (LA) from depithed sugarcane bagasse (DSB) using 1-ethyl-3-methylimidazolium hydrogen sulfate [EMim][HSO 4 ] ionic liquid (IL) were investigated. The effect of temperature (100–220 °C), reaction time (2–12 h), and ionic liquid loading (1–4 g) was assessed using response surface methodology based on the Box-Behnken design. The optimum conditions were found to be 100 °C, 7 h, and 4 g of IL, which yielded 54.6% of LA from DSB. The analysis of variance (ANOVA) indicated that the design model was significant at the 95% confidence level. The pareto chart revealed that IL loading had the most significant effect on the production of LA, followed by temperature and reaction time. The P-values also showed that these were the significant model terms. There is a strong correlation between temperature and IL loading. Solvent optimization revealed that the type of solvent used in the LA production has a significant effect on LA yield. Water was used as the control solvent for this study. Methyl isobutyl ketone (MIBK) yielded the highest LA (62%) from all the solvents that were used. Graphic Abstract