Adsorption Separation of Reaction Product From Ionic Liquid Reaction Mixture for Conversion of Biomass Into 5-Hydroxymethylfurfural (HMF)

Separation of non-volatile reaction products in ionic liquid catalytic processes has been a challenging problem yet is crucial for practicality, due to high viscosity, non-volatility, and easy solidification of the ionic liquid fluid. In this presentation, we'll discuss separation of 5-hydroxymethylfurfural-type (HMF) products produced from catalytic conversion of sugars in an ionic liquid fluid. HMF is regarded of large potential as a polymer monomer to replace the petroleum oil-derived polyester. The ionic liquid catalytic process provides fairly highly activity and HMF yield (>90%) compared to other solvent-based or solid catalyst-based processes. Extraction of HMF by use of an organic solvent is associated with low solubility and selectivity, which would result in complex process flow diagrams and high cost. Several solid adsorbents are identified in this work to provide high adsorption capacity (>10 wt. %) for selective adsorption of HMF from an ionic liquid/water reaction mixture. The saturated adsorbent can be readily regenerated by water and solvent washing, and the adsorbent shows stable performances over repeated adsorption/regeneration cycles. Production of 97% pure HMF is shown with a zeolite adsorbent-packed adsorption column. The adsorption can be an effective separation process technology for ionic liquid catalytic processes, where separation by changing temperatures (distillation or crystallization) is not feasible.