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 ℃, 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. [ABSTRACT FROM AUTHOR]