Aromatic sulfonic acid-catalyzed conversion of safflower stalk into levulinic acid

Safflower stalk is a suitable lignocellulosic biomass that can replace fossil resources for the production of platform chemicals. In this study, the production of levulinic acid (LA) from safflower stalk using aromatic sulfonic acids as environmentally friendly catalysts was investigated. A Taguchi experimental design was used to determine the conditions for the highest product yield. The variations of valuable by-products such as 5-HMF, formic acid, and acetic acid, which may occur depending on the reaction conditions were also analyzed. Optimum conditions for maximum LA yield were found using para-toluenesulfonic acid (PTSA) with concentration of 0.3 M, solvent/biomass ratio as 20 at a temperature of 200 degrees C. Experiments were also carried out to verify the optimum LA yield found using analysis of variance (ANOVA). Comparison experiments were performed with sulfuric acid (H2SO4) under optimum conditions, and it was concluded that PTSA could be an alternative catalyst to H2SO4 in terms of LA yield.