Integrated process for 2,5-furandicarboxylic acid production from fructose via NaCl-promoted dehydration and Au/HT-catalyzed oxidation

This study proposes a conceptual design of an integrated system for converting fructose into 2,5-furandicarboxylic acid (FDCA). The proposed process involves two biphasic catalytic reactors, facilitating the fructose dehydration to 5-hydroxymethylfurfural (HMF) and subsequent oxidation to FDCA, without requiring intermediate purification steps. Fructose dehydration is conducted in a biphasic system utilizing water and methyl isobutyl ketone (MIBK). In this first reactor, sodium chloride is employed to enhance HMF production from fructose in absence of an acid catalyst. Following the dehydration step, the organic phase containing HMF is extracted using a decanter and subsequently introduced into the oxidation reactor. In this second stage, water is added to form a biphasic solvent system, allowing FDCA to be produced in the aqueous phase. This configuration not only simplifies the process by eliminating the need for energy-intensive separation and purification units, but also facilitates efficient FDCA production. Since FDCA is poorly soluble in water, it can be easily crystallized from the aqueous phase without requiring distillation of organic solvents. The oxidation step, catalyzed by gold supported on hydrotalcite (Au/HT), achieves a 100% FDCA yield. The absence of intermediate products ensures high purity of FDCA. Overall, the global FDCA yield starting from fructose is 71%.