One-pot conversion of glucose to 5-hydroxymethylfurfural under aqueous conditions using acid/base bifunctional mesoporous silica catalyst

Abstract

One-pot conversion of carbohydrate-derived biomass compounds to 5-hydroxymethylfurfural (HMF) using an environmentally green solvent such as water is meritorious, yet challenging, which requires the strategic design of catalysts. We prepare an ordered bifunctional organocatalyst (MS-AB) containing 3-aminopropylacetic acid grafted within the silica nanocage that converts glucose-to-HMF, exhibiting the highest HMF yield (60 wt.%/85.7 mol%) in water and under microwave conditions. Moreover, the calculated activation energies (150–170 °C) for glucose isomerization to fructose, vis-à-vis dehydration to HMF were 59.06 and 138.05 kJ mol−1, respectively which can even be comparable with the metal-catalyzed reactions. Further evidence was shown from the rate constant values, indicating fructose dehydration is faster (rate constant: k2: 1.92 x 10−2 to 1.13 x 10−1 min−1) than glucose isomerization (rate constant: k1: 2.5 to 5.3 x 10−3 min−1). Considering the advantages associated with MS-AB, the results might showcase the potential of organocatalyst for sustainable utilization of lignocellulosic biomass to platform chemicals.