(580d) Integrated Pathway for the Efficient Conversion of Lignocellulosic Sugars to HMF

5-hydroxymethylfurfural (HMF) is a versatile bio-derived platform molecule that can be converted to drop-in fuels and used as precursors for synthetic materials such as 2,5-diformylfuran and 2,5-furan dicarboxylic acid (FDCA). Naturally-abundant glucose is the obvious choice of starting material; however low yields due to formation of humins and energy-intensive product recovery has hindered the commercial viability. Several studies have shown that HMF yields are higher from fructose than glucose, however naturally-occurring resources of fructose are limited. Further, the commercially established process of enzymatic isomerization of natural-abundant glucose to fructose is equilibrium limited. To address these challenges, we present an integrated process - Simultaneous-Isomerization-and-Reactive-Extraction (SIRE) followed by Back-Extraction (BE) process, for efficient conversion of lignocellulosic glucose into HMF via fructose. First, in a biphasic SIRE process, aqueous glucose is enzymatically isomerized to fructose using commercially-established immobilized GXI. Simultaneously, reactive-extraction of fructose is selectively facilitated by naphthalene-2-boronic acid (N2B) into an immiscible octanol phase. Next, the fructose-rich octanol phase is contacted with acidic water to back-extract (BE) the sugars from the immiscible octanol phase. Finally, the acidic fructose-rich aqueous solution obtained after SIRE-BE process is mixed with a low-boiling co-solvent 1,2-dimethoxyethane (DME) to form a homogenous solvent mixture where dehydration to HMF occurs. After optimizing reaction parameters, we report that with a concentrated sugar feed of 25 wt%, high HMF yield of 87 mol% can be achieved at 120 °C in 30 mins. Fructose is completely converted while glucose remains largely unreacted. We also demonstrate a pathway to separate the unreacted glucose, HMF and DME by phase splitting using toluene. Our techno-economic assessment estimates a minimum selling price to be $1.22/kg-HMF. When HMF is recovered in toluene for 2,5-diformylfuran and FDCA application, the minimum selling price is estimated to be $1.19/kg-HMF (toluene-free basis), which is best reported so far in literature.