Production of Levulinic Acid from Coconut Residues (Cocos nucifera) Using Differents Approaches

This study aims to validate and investigate the power of green coconut biomass (mesocarp) for the production of levulinic acid (LA). Several methods have been applied to characterize this biomass physically and chemically, in order to provide an assertive direction in the use of this residue. The LA conversion was performed with different catalysts, hydrochloric acid (HCl) and sulfuric acid (H2SO4). The conversion reactions were performed by varying time (t) and temperature (T) according to the optimum conditions described in the literature for each catalyst. In order to increase the yield of LA, the biomass was pretreated with sulfuric acid (H2SO4), sodium hydroxide (NaOH), and water (H2O in soxhlet) solutions. There were significant increases in the release of sugars, xylose, and arabinose (p < 0.05), after the pretreatments with NaOH solution (assay 9). The maximum yield of LA was 43.8% under the following reaction conditions: 3 h, 180 °C, and 0.045 M of hydrochloric acid (HCl). In addition to the levulinic acid, the 5-hydroxymethylfurfural (HMF) and furfural (FF) furanics were also quantified with yields of 13.4% and 4.4% respectively. The results have shown the power of green coconut shells within biorefineries to produce value-added chemicals.