Stable and Water-Tolerant Deep Eutectic Solvent from Biomass-Derived 5‑Hydroxymethylfurfural (HMF) and Levulinic Acid

Area of Science:

• Green Chemistry and Sustainable Processes
• Biomass Valorization and Biorefining
• Chemical Engineering and Materials Science

Background:

• Sustainable biomass valorization requires greener extraction systems.
• 5-hydroxymethylfurfural (HMF) and levulinic acid (LEV) are key bioderived platform molecules often co-produced during biomass processing.
• Efficient and eco-friendly recovery methods for these molecules are crucial for biorefinery development.

Purpose of the Study:

• To investigate the spontaneous formation of a stable liquid phase between HMF and LEV.
• To characterize the physicochemical properties and behavior of this HMF-LEV liquid phase.
• To evaluate its potential as a sustainable solvent for HMF extraction in biorefining.

Main Methods:

• Differential Scanning Calorimetry (DSC) for thermal analysis.
• Thermodynamic modeling to understand phase behavior.
• Nuclear Magnetic Resonance (NMR) spectroscopy, Molecular Dynamics (MD), and Density Functional Theory (DFT) for structural and dynamic analysis.

Main Results:

• A stable liquid phase of HMF and LEV forms over a broad compositional range, exhibiting eutectic behavior near x_HMF = 0.39 (258 K).
• The HMF-LEV mixture displays deep eutectic solvent (DES)-like properties, remaining liquid even with low water content.
• Hydrogen bonding between HMF and LEV drives nonideal mixing; water enhances structuration at the eutectic composition.

Conclusions:

• The HMF-LEV liquid phase can be generated *in situ* within biomass surrogates, significantly improving HMF extraction efficiency.
• This system eliminates the need for additional organic extractants, presenting a solvent-minimized recovery route.
• The HMF-LEV system is a promising, bioderived liquid platform for resource-efficient biorefinery schemes.