Employing renewable and widely available feedstock of cellulose as a raw material for 5-hydroxymethylfurfural (HMF) production opens up the possibility of sustainable biorefinery schemes that do not compete with the food supply. In this work, novel and efficient Brønsted acidic polymer nanotubes were successfully prepared by chemical conjugating grafting −SO3H groups onto the surface of polydivinylbenzene (PDVB) nanotubes, which were derived from cationic polymerization of divinylbenzene. By simply adjusting the grafting amounts of hydrophilic −SO3H groups, catalysts with varied hydrophobic and hydrophilic surface wettability (i.e., catalyst-110° and catalyst-10°) could be obtained. It was demonstrated that as-prepared catalyst-10° possessed the higher strong (143 μmol g–1), very strong (614 μmol g–1), and total acidity (786 μmol g–1) than those of catalyst-110°. Besides, the catalytic performance of the synthesized catalyst-110° and catalyst-10° were investigated and compared for the conversion of cellulose to HMF in an ionic liquid (i.e., 1-ethyl-3-methyl-imidazolium chloride, [EMIM]-Cl) system. Particularly, catalyst-110° exhibited the highest HMF yield of 34.6% on a molar basis, which was comparable with that of catalyst-10° (i.e., 37.1%), indicating that its hydrophobic nature was beneficial for decreasing side-reaction of HMF which tend to convert to some other byproducts during the very one-pot reaction. Furthermore, both catalysts can be easily recovered and reused for at least four times without significant loss of their catalytic activities. This work was the continue efforts for fabrication and application solid catalyst for excellent conversion of one-pot cellulose to HMF.

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Ac onfocal laser scanning microscope (CLSM, Leica, TCSSP5II, Germany) was used for fluorescence testing. Morphology investigations were analyzed by means of field emission SEM, which was Scheme2.Schematicillustration for the synthesis of macroporous matrixes by high internal phase emulsion polymerization.

Stable oil‐in‐water high internal phase emulsions (HIPEs) with an internal phase volume fraction of 85 % were stabilized using Tween 85. The prepared poly(HIPEs) were first investigated as adsorbents to treat water polluted with CrIII, and then the catalysts with Lewis acidic sites was synthesized. The catalysts with Brønsted acidic sites were obtained by ion‐exchanging. The as‐prepared HIPEs–CrIII (PEs–CrIII) and HIPEs–SO3H (PEs–SO3H) possess open‐cell structure, interconnecting pores, and strong acidity, they are utilized as highly efficient catalysts for the conversion of biomass to 5‐hydroxymethylfurfural (HMF). These results showed maximum production yields for cellulose, glucose, and fructose of 37.0 %, 58.0 %, and 80.8 %, respectively. PEs–CrIII and PEs–SO3H can be very easily recycled at least four times without significant loss of activity. Herein, a new method is presented to transform cellulose by using two catalysts in a one‐pot process for meeting the varying demands involved at different reaction stages.

The Whole process of synthesis of HPFCs by Pickering high internal phase emulsions and application in conversion of cellulose to HMF.