Self‐organization of ionic liquid‐modified organosilica hollow nanospheres and heteropolyacids: efficient preparation of 5‐HMF under mild conditions

As a biomass‐derived platform molecule, 5‐hydroxymethylfurfural (5‐HMF) is a highly desirable feedstock for manufacturing of high value‐added chemicals ranging from starting materials for polyesters to biofuels. In this work, we reported the fabrication of a series of multicomponent solid acid catalysts based on heteropolyacids immobilized ILs‐modified organosilica hollow nanospheres (denoted as PW12‐ILs‐Cn‐HNS), in which PW12 (PW12=H3PW12O40 ⋅ xH2O) provides Brønsted acid site, ILs show strong electrostatic interactions with PW12, Cn (Cn=alkyl chain) is attached for hydrophobicity and HNS represents organosilica hollow nanospheres. When applied for catalytic dehydration of fructose to 5‐HMF, the PW12‐ILs‐C4‐HNS catalyst with 15.2 % PW12 loading exhibited the best dehydration activity to 5‐HMF with 93.7 % yield in DMSO at 100 °C in 2 h. Compared with 2D hexagonal and 3D interconnected structures, the excellent porosity properties of hollow nanospherical structure can provide a high population of the PW12 sites and enough confined nanospace for the dehydration of fructose. Moreover, the PW12‐ILs‐Cn‐HNS catalyst showed excellent stability over six catalytic cycles without obvious loss of activity. Most importantly, careful identification of the observed intermediates revealed crucial information for the dehydration process of fructose to 5‐HMF. As such, the proposed heterogeneous catalysts show great potential in biomass conversion processes