A sustainable and low-cost route to 2,5-furandicarboxylic acid by carboxylation of biomass-based furoic acid and CO2

CO2 carboxylation is an important and attractive way of CO2 resourceful utilization, which could synthesize carboxylic acids. As the most promising alternative to terephthalic acid, 2,5-furandicarboxylic acid (FDCA) could be produced by direct carboxylation of the biomass-derived 2-furoic acid (FA) and CO2 promoted by Cs2CO3, but the high cost of cesium limits the development of the route. Herein, low-cost K2CO3 was only used to promote the carboxylation of FA and CO2 for the synthesis of FDCA, whose feasibility was demonstrated by theoretical calculations and experiments. However, the reaction system was strongly influenced by temperature only using K2CO3. The addition of low-cost HCOOK could effectively decrease the reaction temperature, and thus enhance the practicality of the reaction system. Based on experimental and theoretical simulations, it was revealed that the addition of HCOOK not only significantly lowered the melting temperature of the reaction system, but also effectively reduced the activation energy barrier of the hydrogen capture step. The investigation would provide potentiality for a large production of FDCA.