(518e) High Yield Synthesis of HMF from Glucose in the Water-Organic Solvent System

5-hydroxymethylfurfural (HMF) is a versatile bio-derived platform molecule obtained dehydration of glucose or fructose. HMF selectivity and yield are higher when fructose is the starting material rather than glucose, but glucose is naturally-abundant in lignocellulose whereas resources of natural fructose are limited. Leveraging our Simultaneous-Isomerization-and-Reactive-Extraction (SIRE) followed by Back-Extraction (BE) process,^1-3 we present an integrated pathway for efficient conversion of glucose into HMF via fructose. In SIRE, aqueous glucose is enzymatically isomerized to fructose and simultaneously extracted into an immiscible octanol phase containing naphthalene-2-boronic acid (N2B) in a biphasic system. Due to the selective binding of N2B to fructose, the octanol phase has a high extraction selectivity for fructose (80-90%). Next, the fructose-rich octanol phase is contacted with acidic water, again in a biphasic system, to back-extract (BE) the sugars from the immiscible octanol phase. The acidic fructose-rich aqueous solution obtained from SIRE-BE is mixed with the co-solvent - 1,2-dimethoxyethane (DME) and heated to allow sugar dehydration and formation of HMF. After optimizing reaction parameters in the water-DME system, we report that with a concentrated sugar feed of 25 wt% (on water-basis, glucose: fructose = 1:4) with a HCl catalyst concentration of 55 mM (water-basis), high HMF yield of 87% (mol HMF formed/mol sugar reacted) can be achieved after dehydration at 120 °C for 30 min. Fructose is completely converted during this reaction, while glucose remains largely unreacted (glucose conversion = 18% (mol sugar reacted/mol sugar added)) . Recovery of HMF from the water-DME system is energy-efficient due to the low heat of vaporization of DME (383 kJ/kg, 85 °C). We also demonstrate a pathway to separate the unreacted glucose, HMF and DME by phase splitting using toluene as the ternary solvent. Our techno-economic assessment of the process estimates a minimum selling price of isolated HMF to be $1.22/kg when glucose is sourced at $0.236/kg.⁴ When HMF is recovered in toluene for 2,5-diformylfuran and 2,5-furan dicarboxylic acid application, the minimum selling price is estimated to be $1.19/kg-HMF (toluene-free basis), which is best reported so far in the literature.

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3. Gogar, R.; Viamajala, S.; Relue, P. A.; Varanasi, S., Techno-Economic Assessment of Mixed-Furan Production from Diverse Biomass Hydrolysates. ACS Sustainable Chemistry & Engineering 2021, 9 (9), 3428-3438.
4. Davis, R.; Tao, L.; Scarlata, C.; Tan, E. C. D.; Ross, J.; Lukas, J.; Sexton, D. Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Catalytic Conversion of Sugars to Hydrocarbons; NREL/TP-5100-62498; National Renewable Energy Lab. (NREL), Golden, CO (United States): 2015; p Medium: ED; Size: 133 p