Catalytic condensation of depithed sugarcane bagasse derived levulinic acid into diphenolic acid

Abstract

Levulinic acid (LA) is a platform chemical that can be produced from biomass. Diphenolic acid (DPA) is a derivative of LA with the potential to replace bisphenol A, a plasticizer. To determine the optimum conditions for DPA production, commercial LA was used with a mild environmentally benign acid, namely, methanesulfonic acid (MsOH). The optimized reaction parameters were time (6 h), temperature (75 °C), and catalyst loading (5.5 g), yielding 65.8% DPA at 90% LA conversion. The response surface methodology (RSM) study indicated that the temperature had the most significant effect on DPA yield, followed by time and catalyst loading. The analysis of variance (ANOVA) revealed that the model was able to satisfactorily predict the DPA yield. To determine the effect of catalyst on DPA production from commercial LA, ionic liquids (ILs), MsOH, and sulfuric acid were used. IL catalysts produced 59 to 68% of DPA, MsOH produced 65.6% of DPA, and sulfuric acid produced the maximum DPA of 74%. The study of LA: phenol ratio revealed that more reactants (2:5) yielded the most DPA (86.35%). The optimized reaction conditions were then used to produce DPA from LA derived from depithed sugarcane bagasse (DSB), which yielded 64.5% of DPA.