One-pot ethanolysis of carbohydrates to promising biofuels: 5-ethoxymethylfurfural and ethyl levulinate

5-Ethoxymethylfurfural (EMF) and ethyl levulinate (EL) have been considered as the new promising biofuels. A comparative study was conducted for the direct conversion of carbohydrates into EMF and EL in different medium containing ethanol. The distribution and formation kinetics of EL, EMF, 5-hydroxymethylfurfural (HMF) and levulinic acid ( LA) in pure ethanol and ethanol/organic solvent medium were compared, and the results showed that the addition of n-hexane can improve the accumulation of EMF. When the volume ratio of ethanol to n-hexane was 6:4, 66.29% of EMF yield can be obtained from fructose at 120 degrees C and 180 min. The total yield of the EMF and EL can reach to 83.71%, increased by 5.73% compared with that in pure ethanol medium. Moreover, water addition can suppress the etherification of HMF to EMF and promote the rehydration of HMF to LA in the process. On the basis, a putative reaction pathway for the conversion of carbohydrates in ethanol/n-hexane medium was proposed. (C) 2017 Curtin University of Technology and John Wiley & Sons, Ltd.