Carbocatalyst in biorefinery: Selective etherification of 5-hydroxymethylfurfural to 5,5′(oxy-bis(methylene)bis-2-furfural over graphene oxide

• Etherification of HMF to OBMF could be effectively catalyzed by graphene oxide.
• Water has a great effect on the yield of OBMF during the reaction.
• The existence of oxygen containing groups on GO was important for the catalysis.
• GO can be reused after simple treatments.

Hydroxymethylfurfural (HMF) is an important biomass based building block which can be efficiently produced from carbohydrates, while the utility of HMF warrants further exploration. Herein, we explored a green method for the transformation of HMF into a symmetrical ether named 5′-oxy(bis-methylene)-2-furaldehyde (OBMF) promoted by graphene oxide (GO). HMF conversion in no-polar solvents was obviously higher than that in polar solvents. Water existed in the reaction system could significantly decrease the OBMF yield. Moreover, the high catalytic performance of GO was closely related to oxygen containing groups on GO. A maximum OBMF yield of 86% was obtained under optimized conditions.