Systematic Identification of Solvents Optimal for the Extraction of 5‑Hydroxymethylfurfural from Aqueous Reactive Solutions

To ensure a high efficiency of 5-hydroxymethylfurfural
(HMF) synthesis,
improved solvents for the extraction of HMF from a reactive aqueous
solution were identified using the predictive thermodynamic model
COSMO-RS. Utilizing COSMO-RS as a basis for a systematic solvent selection
has the advantage of potentially saving significant time and effort
by computationally screening several thousand possible solvents. Factors
including temperature, concentration, and fructose addition were used
for experimental validation of the predictive power of COSMO-RS. Continuous
extraction experiments confirmed also kinetics and phase separation
to be important for technical implementation. COSMO-RS predicted o-propylphenol and o-isopropylphenol to
have partition coefficients as high as 10.02 and 9.82, which are roughly
five times higher than the partition coefficient of the previously
known, most effective solvent: 2-methyltetrahydrofuran (PHMF = 2). Therefore, the identification of o-propylphenol and o-isopropylphenol as improved
solvents constitutes a significant efficiency improvement for the
extraction, and by extension for the entire HMF synthesis.