(621dt) High-Yield Conversion of Glucose to 5-Hydroxymethylfurfural (HMF) Under Mild Reaction Conditions

In this study, a novel method is presented for the production of 5-hydroxymethylfurfural (HMF) from the biomass sugar glucose at high conversion under facile reaction conditions. The method consists of three sequential steps. In the first step of this process, glucose is isomerized to fructose, and fructose is reactively-extracted into an organic phase via complexation with an organophilic boronic acid. In the second step, fructose is recovered and concentrated from the organic solvent by back-extraction into an ionic liquid medium. In the third and final step, fructose is dehydrated to produce HMF in high yield. We achieved comparable results for this process with pure glucose and biomass hydrolysate produced from dilute acid pretreatment of corn stover at equal initial glucose concentrations. Candidate organic solvents of octanol, ethyl acetate, and diethyl ether were tested for the process. Octanol was selected based on its immiscibility with water, ability to dissolve boronic acid, sugar extractability, and ionic liquid ([EMIM]HSO4) immiscibility. Five aryl boronic acids (ABAs) identified as a sugar complexing agents were evaluated for their sugar extraction efficiency and fructose selectivity in this experimental system. The compound 4-butoxy-3,5-dimethyl phenylboronic acid (4-BDM)performed best in this application. Important features of this three-step approach, with significant economic implications, are that each of the steps in the process can be conducted at facile temperature and pressure conditions with high product yields. In addition, the process media and catalysts can be easily recycled and reused, further reducing costs by minimizing process inputs.