Efficient aerobic oxidation of 5-hydroxymethylfurfural to 5-hydroxymethyl-2-furancarboxylic acid over porphyrin-based porous organic polymer-supported Ag nanoparticle catalysts

A series of porphyrin-based porous organic polymer-supported Ag nanoparticle, Ag(0)@POP-x were prepared by the reaction pathway of ion coordination followed by hydrogen reduction. The resulting composite Ag(0)@POP-6.52 shows excellent catalytic performance toward the selective oxidation of HMF to HMFCA, and an impressive HMFCA yield of 97.2% (Na2CO3 2 eq, O2 2.0 MPa 90 min, 100 °C). Analysis techniques such as ICP-OES, XRD, TEM, SEM, N2 adsorption-desorption, and XPS was employed to characterize the structure and properties of Ag(0)@POP-6.52. The reaction conditions including the type of base and solvent, base and catalyst dosage, oxygen pressure, reaction temperature and time were studied in detail to improve the yield of HMFCA. Furthermore, the catalytic stability of the Ag(0)@POP-6.52 was evaluated by leaching and reusing tests, the results shows that the catalyst has good stability and robustness structure. Finally, the other aldehydes oxidation over Ag(0)@POP-6.52 was tested for investigation the substrate scope of Ag(0)@POP-6.52.