In this study, a magnetically recoverable nano photocatalyst (Fe3O4/Fe2O3/TiO2/Ag) was prepared using Ag nanoparticles supported on anatase TiO2-coated Fe3O4/Fe2O3 nanoparticles. The photocatalyst was characterized by FT-IR, XRD, BET-BJH, ICP-AES, TEM, DLS, VSM, FESEM, and EDX and found to have excellent catalytic activity for synthesizing HMFCA (5-hydroxymethylfurfural-2-carboxylic acid) from HMF (5-hydroxymethylfurfural) in the presence of a deep eutectic solvent under white light irradiation. An appropriate HPLC method was established to obtain good separation of the possible metabolic substances. The advantages of this protocol consist of the use of a stable and safe light source, an environmentally friendly solvent, magnetic recyclability, and long-term stability of the catalyst for at least six consecutive runs. The synthesis of HMFCA using this method meets the requirements of green, sustainable synthetic chemistry and has potential applications in pharmaceutical chemistry and organic synthesis. Considering the yield of 98%, this novel protocol demonstrates a potential for one-pot synthesis of renewable HMFCA and a valuable product. Overall, this study showcases the advantages of green chemistry to make it a promising avenue for future research.
