One-step liquid-phase ammonia oxidation of 5-hydroxymethylfurfural to 5-hydroxymethylfurfurylamide

5-hydroxymethylfurfurylamide (HMFA) is an important nitrogen-containing derivative of 5-hydroxymethylfurfural (HMF). At present, the synthesis of HMFA from readily available, low-cost HMF is extremely challenging. In this study, one-step, highly efficient liquid-phase ammonia oxidation of HMF to HMFA was realized with MCM-41 as the catalyst and H 2 O 2 as the green oxidant. Adjusting the NH 3 ·H 2 O amount to control an appropriate pH value of the reaction solution was beneficial for the formation of the HMFA. Under mild reaction conditions, the HMF conversion and HMFA yield were 92.5% and 87.5%, respectively. Furthermore, the reaction could be extended to the synthesis of corresponding amides from a series of fatty aldehydes, heterocyclic aldehydes and aromatic aldehydes. A plausible reaction process involving the formation and transformation of hemiimine as an intermediate was proposed based on the online sampling experiments, in-situ IR study and DFT calculations.