The reaction pathways of 5-hydroxymethylfurfural conversion in a continuous flow reactor using copper catalysts

Abstract

The transformation of 5-hydroxymethylfurfural is investigated using supported and bulk copper oxide catalysts. We show that the selectivity to 5-methylfuraldehyde or 2,5-diformylfuran can be controlled by the solvent and the carrier gas. The use of water as the solvent and N₂ as the carrier gas led to the highest conversion and most selective pathway to 2,5-diformylfuran. Quasi in situ X-ray photoelectron spectroscopy and H₂-TPR measurements revealed that H₂O can re-oxidise Cu, significantly enhancing the selectivity to 5-methylfuraldehyde. Subsequent density functional theory calculations revealed more precisely the role of water in the reaction mechanism.