High-Efficiency Preparation of 2,5-Diformylfuran with a Keto-ABNO Catalyst Under Mild Conditions

In this paper, we report a new catalytic system for realizing the rapid and efficient oxidation of 5-hydroxymethylfurfural (HMF). First, we used 9-azabicyclo [3.3.1]nonan-3-one-N-oxyl (keto-ABNO) as a catalyst for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) in acetic acid. Then, we systematically studied the important reaction parameters, including the solvent, co-catalyst, and temperature. The results demonstrate that the acidic solvent used is crucial for the efficient oxidation of HMF to DFF. Under optimal conditions, we achieved a 93.4% yield of DFF within half an hour at room temperature. We also proposed the possible mechanism for this system.