(632f) The Role of Water in the Hydrodeoxygenation of 5-Hydroxymethylfurfural from Lignocellulosic Feedstocks

Finding fossil fuel replacements as carbon sources is crucial to a carbon-neutral future. 5-hydroxymethylfurfural (HMF) is one of the platform chemicals that can serve as an answer to this demand. The hydrodeoxygenation reaction of HMF over Ru/C yields 2,5-dimethylfuran (DMF), paving way to the broad utilization of HMF. We recently reported effective solvent extraction of HMF from the reactive aqueous phase using water-organic biphasic systems.¹ In these systems, the organic phase is saturated with water, typically around ten weight percent of the organic phase. Separation of water from such organic phase via distillation is difficult due to the instability of HMF and the azeotropic systems often formed between water and the organic solvents. Interestingly, we report here that water improves the selectivity of the HMF HDO reaction while decreasing the HMF conversion. Reaction pathway analysis via monitoring the species distribution over the course of the reaction sheds light on the water’s role in the HMF HDO reaction. To elucidate whether catalyst reoxidation occurs, the Ru/C catalyst is subject to a variety of treatment conditions. Besides, the effects of temperature, the presence of levulinic and formic acids, and the presence of chloride ions from the previous fructose dehydration step, are also investigated. Additionally, we complement our experimental investigation with a technoeconomic analysis (TEA) of a proposed water-organic biphasic system for HMF production from fructose to show the impact of the design on the overall economics of future lignocellulosic biorefineries.

1. Wang, Z.^#; Bhattacharyya, S.^#; Vlachos, D. G., Solvent selection for biphasic extraction of 5-hydroxymethylfurfural via multiscale modeling and experiments. Green Chem. 2020, 22 (24), 8699-8712.