Dehydration of Carbohydrates to 5-Hydroxymethylfurfural over Lignosulfonate-Based Acidic Resin

Lignosulfonate-based renewable solid acids were first utilized as effective catalysts for fructose dehydration to produce 5-hydroxymethylfurfural (HMF). Among the investigated catalysts, the LF resin synthesized with formaldehyde and sodium lignosulfonate demonstrated the highest activity and good stability. Over it, ∼90% HMF carbon yield was reached at 393 K. On the basis of the characterization results of N2-physisorption, chemical titration, and microcalorimetric measurement of NH3 adsorption, the outstanding performance of LF resin should be interpreted by its higher acid strength and/or the synergistic effect of adjacent −SO3H, −COOH and phenolic −OH surface functional groups. We also explored the applicability of the LF resin for HMF production using other cheaper carbohydrates. Here, 73% HMF carbon yield was obtained from inulin hydrolysis/dehydration after the reaction was conducted over the LF resin at 393 K for 2.5 h.