Abstract

• Lignocellulosic biomass is a long-term alternative carbon source and could be used as raw material to prepare liquid fuels and valuable chemicals. Among these chemicals, levulinic acid is a valuable platform compound, which is intermediate for preparing alternative petroleum-based chemicals such as plasticizer, coating, and fuel additives. This research work focused on the extraction of levulinic acid from lignocellulosic biomass such as sugarcane bagasse by acid-catalyzed hydrothermal method. The physico-chemical characteristics of sugarcane bagasse such as cellulose, hemicellulose, lignin, extractives, and ash content were analyzed by using TAPPI and AOAC methods. Dilute sulfuric acid pretreatment of sugarcane bagasse was firstly carried out with different variables such as solid to liquid ratio and reaction time for the optimum extraction of cellulose content. Acid-catalyzed hydrothermal treatment of pretreated sugarcane bagasse was performed by controlling reaction temperature, reaction time, concentration of hydrochloric acid (Bronsted acid) and concentration of aluminium chloride (Lewis acid). Central composite design was used to arrange experimental runs to optimize the cellulose content of sugarcane bagasse during dilute sulfuric acid pretreatment and the yield percent of levulinic acid based on concentration during acid-catalyzed hydrothermal method. For calculating the yield percent of levulinic acid based on concentration, the absorbance of levulinic acid was measured by UV visible spectroscopy at 266 nm (λmax). The maximum yield percent of levulinic acid based on concentration from sugarcane bagasse (89.64 ± 3.14 %) with the 6.78 % composition of levulinic acid was obtained by synergistic use of 6.4 % (v/v) HCl and 2.3 % (w/v) AlCl3 at 171 ºC for 3 hr and 6 min. The levulinic acid under optimum conditions from pretreated sugarcane bagasse was identified by UV-Visible Spectroscopy for λmax, FTIR Spectroscopy for functional groups and Gas Chromatography-Mass Spectroscopy (GC-MS) for the presence of levulinic acid.