Combination of Bronsted and Lewis Polymeric Catalysts for Efficient Conversion of Cellulose into 5-Hydroxymethylfurfural (HMF) in Ionic Liquids

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 Cr-III, and then the catalysts with Lewis acidic sites was synthesized. The catalysts with Bronsted acidic sites were obtained by ion-exchanging. The as-prepared HIPEs-Cr-III (PEs-Cr-III) 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-Cr-III 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.