Production of 2,5-Furandicarboxylic Acid from Lignocellulosic-Biomass-Derived Glucaric Acid in an Ionic Liquid Combined Acid Catalyst Solvent System

In this study, a system for producing 2,5-furandicarboxylic acid (FDCA) from glucaric acid was developed. To enhance the conversion efficiency and recyclability of the catalyst, an ionic liquid combined acid catalyst (ILCA) system was developed. Thermogravimetric analysis of the hydrobromic-acid-based ILCA demonstrated that its thermal stability was enhanced due to interactions between the ionic liquid and acid catalyst, as evidenced by an increased decomposition temperature. Through reaction condition screening, the maximum FDCA production was accomplished at a reaction temperature of 160 °C, reaction time of 60 min, and glucaric acid concentration of 5 wt % in hydrobromic acid as an acid catalyst (70.6% FDCA yield). Among the acid catalysts, hydrobromic acid showed the highest FDCA yield due to the formation of the brominated substituted intermediate. The performance of ILCA was maintained after the fourth use, and the catalytic activity was regenerated by additional ion-exchange resin treatment. The produced FDCA was separated during ILCA recycling and purified by an activated carbon treatment. The conversion of glucaric acid derived from enzymatic hydrolysates into FDCA achieved a yield of 70%, comparable to that obtained from pure glucaric acid. The newly developed process is feasible for the effective utilization of feedstocks generated on the biosugar platform.