Sustainable recovery and recycling of acidic ionic liquid in 5-ethoxymethylfurfural production via bipolar membrane electrodialysis

Acidic ionic liquids have been proven effective as homogeneous catalysts in preparing 5-ethoxymethylfurfural the fuel additive and platform chemical. Homogeneous catalysis specialty and complicated electrolyte composition limited direct recovery of acidic ionic liquids after 5-ethoxymethylfurfural preparation. In this study, a bipolar membrane electrodialysis (BMED)-based strategy was designed for controllably recovering and regenerating acidic ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate [Bmim][HSO4] after 5-ethoxymethylfurfural preparation from fructose. Key factors in recovery of ionic liquid [Bmim][HSO4] were studied to ascertain the technical and financial feasibility of the electrodialysis-assisted strategy. The maximum recovery ratio of [Bmim][HSO4] approached 96.2% and the minimum recovery cost was less than 0.1% of [Bmim][HSO4] purchase cost. Insight developed by the work revealed a viable solution for efficient and integral recycling of acidic imidazole ionic liquid in the high-value conversion of biomass.