Polyaniline‐Grafted VO(acac)2: An Effective Catalyst for the Synthesis of 2,5‐Diformylfuran from 5‐Hydroxymethylfurfural and Fructose

Herein, polyaniline‐grafted vanadyl acetylacetonate [VO(acac)2] was prepared and used as an effective catalyst for the oxidation of 5‐hydroxymethylfurfural (HMF) under atmospheric oxygen pressure. A high HMF conversion of 99.2 % was obtained after 12 h at 110 °C, and 2,5‐diformylfuran (DFF) was obtained in 86.2 % yield. More importantly, the one‐pot conversion of fructose into DFF was also realized with two binary catalysts: Amberlyst‐15 and polyaniline–VO(acac)2. Amberlyst‐15 was used for the acid‐catalyzed dehydration of fructose into HMF, followed by the in situ oxidation of HMF catalyzed by polyaniline–VO(acac)2. DFF could be obtained in a yield of 42.1 % from fructose by using the one‐pot reaction, whereas two consecutive steps gave a higher DFF yield of 71.1 %. Owing to the facile catalyst preparation and low cost, this method showed a promising potential for the synthesis of DFF from abundant carbohydrates.