Porous solid acid with high Surface area derived from emulsion templating and hypercrosslinking for efficient one-pot conversion of cellulose to 5-hydroxymethylfurfural

This work addressed efficient one-pot conversion of cellulose to 5-hydroxymethylfurfural by porous solid acid in the presence of 1-ethyl-3-methyl-imidazolium chloride ([Emim]Cl). On the basis of stable water-in-oil pickering high internal phase emulsions (HIPEs), porous solid acid (HC-PDVB-SS-SO3H) was prepared by polymerizing divinylbenzene (DVB) and sodium p-styrenesulfonate (SS), succedent sulfonation in H2SO4 and hypercrosslinking process. HC-PDVB-SS-SO3H with a stable network exhibited mesopores within a macropore structure, high BET specific surface area and more super-strong acid sites. To test catalytic activity, the reaction conditions were optimized via response surface methodology, and the sequence of the three variables affecting HMF yield followed the order, temperature > reaction time > amount of catalyst. By comparing with the other as-prepared porous solid acid, it can also be concluded that BET specific surface area and super-strong acid site both played key roles in cellulose conversion. Moreover, HC-PDVB-SS-SO3H was very easily reused at least four times without significant loss of activity.