Efficient conversion of corn stover into 5-ethoxymethylfurfural catalyzed by zeolite USY in ethanol/THF medium

An efficient and green conversion process of producing 5-ethoxymethylfurfural (EMF) from corn stover was developed. The solid zeolite USY provided the good catalytic performance in ethanol medium with tetrahydrofuran (THF) as co-solvent, which can promote the formation of EMF, reducing the formation of ethyl levulinate and 5-hydroxymethylfurfural. The reaction conditions were optimized via response surface methodology leading to a maximum EMF yield of 21.8% in ethanol/THF (volume ratio 1:1) under the conditions of 168 °C, 1 wt% USY loading and 2.9 h. Meanwhile, USY can be reused in five consecutive reaction runs with high activity, upholding the same initial activity and structural integrity. A plausible reaction pathway for the conversion of corn stover to EMF in ethanol/THF medium was further proposed. This study showed that the improved catalytic system presents an efficient method for direct production of EMF from lignocellulosic biomass.