Catalytic upgrading of carbohydrates into 5-ethoxymethylfurfural using SO3H functionalized hyper-cross-linked polymer based carbonaceous materials

Abstract

Sulfonic acid modified organic hyper-cross-linked polymer (HCP) based carbocatalyst with variable –SO3H density and porosity, was synthesized for the one-pot conversion of biomass derived carbohydrates into potential fuel candidate 5-ethoxymethylfurfural (EMF). The structural characterizations revealed that the porous structure of HCP was well maintained after sulfonation process, thus rendering good structure and high Brϕnsted acid density for the one-pot dehydrative etherification reaction. The as-prepared HCP materials exhibited promising catalytic performance for ketoses conversion, which yielded 78.9% of EMF along with 15.4% 5-hydroxymethylfurfural (HMF) and 4.6% ethyl levulinate (EL) using fructose as starting material in ethanol-DMSO biphasic system. Meanwhile, considerable increase in EMF yield from glucose based carbohydrates was attained when adding slight amounts of Lewis acid AlCl3 to reaction protocol. The HCP based catalyst was able to be reused several times without significant loss in catalytic activity. More importantly, the HCP materials were also highly active in other related acid-catalyzed reactions, including esterification, transesterification and dehydration.