Bronsted Acidic Polymer Nanotubes with Tunable Wettability toward Efficient Conversion of One-Pot Cellulose to 5-Hydroxymethylfurfural

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 Bronsted 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 degrees and catalyst-10 degrees) could be obtained. It was demonstrated that as-prepared catalyst-10 degrees possessed the higher strong (143 mu mol g(-1)), very strong (614 mu mol g(-1)), and total acidity (786 mu mol g(-1)) than those of catalyst-110 degrees. Besides, the catalytic performance of the synthesized catalyst-110 degrees and catalyst-10 degrees 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 degrees exhibited the highest HMF yield of 34.6% on a molar basis, which was comparable with that of catalyst-10 degrees (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.