Influence of Salts on the Partitioning of 5-Hydroxymethylfurfural in Water/MIBK

Abstract

This study investigates the influence of electrolytes on the performance of extracting 5-hydroxymethylfurfural (HMF) from aqueous media using methyl isobutyl ketone (MIBK). For that purpose, liquid-liquid phase equilibria (LLE) of quaternary systems containing HMF, water, MIBK and salts were measured at atmospheric pressure and 298.15 K. The salts under investigation were composed of one of the anions NO(3-), SO4(2-), Cl(-), or CH3COO(-) and of one of the alkali cations Li(+), Na(+), or K(+). On the basis of these LLE data, the partition coefficient of HMF between the aqueous and the MIBK phase KHMF was determined. It could be shown that KHMF significantly depends on the kind and concentration of the added salt. Weak electrolytes (e.g., sulfates, acetates) caused salting-out, whereas nitrates caused salting-in of HMF to the aqueous phase. Unexpectedly, LiCl caused salting-out at low LiCl concentrations and salting-in at LiCl concentrations higher than 3 mol/kgH2O. The model electrolyte perturbed-chain SAFT (ePC-SAFT) was used to predict the salt influence on the LLE in the quaternary systems water/MIBK/HMF/salt in good agreement with the experimental data. On the basis of ePC-SAFT, it could be concluded that the different salting-out/salting-in behavior of the various salts is mainly caused by their different tendency to form ion pairs in aqueous solutions.

Influence of electrolytes on liquid-liquid equilibria of water/1-butanol and on the partitioning of 5-hydroxymethylfurfural in water/1-butanol

“…This behavior is also predicted qualitatively correct with ePC-SAFT; the maximum of K ୌ ୵ predicted with ePC-SAFT is slightly over predicted compared to the experimental data. In a previous work [39] this unexpected behavior was investigated; it was observed that strong cation/anion attractions (the formation of ion pairs) strongly contributes to the salting-out of HMF from the aqueous phase. In contrast, the strongly hydrated Li+ ions in aqueous LiCl solutions were found to cause the salting-in of HMF at high LiCl molalities.…”

“…De Hemptinne and Lin correlated mean ionic activity coefficients, osmotic coefficients and solid-liquid equilibria of systems containing electrolytes and neutral components [26]. Further, equations of state based on Statistical Associating Fluid Theory (SAFT) [27] were developed recently to model electrolyte systems [28,29] [39].…”

“…In contrast, the dielectric constant used in ePC-SAFT is assumed to have the value of water and to be only temperature-dependent. This procedure was developed in previous works [39],…”

Fast Screening of Solvents for Simultaneous Extraction of Furfural, 5-Hydroxymethylfurfural and Levulinic Acid from Aqueous Solution Using SMD Solvation Free Energies

“…5 An efficient extraction requires an adequate solvent, which should have low miscibility with water and lead to a high partition coefficient for each compound. Recent experimental studies have investigated different solvents for extraction [7][8][9][10] and some authors have suggested that 2-butanol and 2-butanone are effective for HMF, while methyl isobutyl ketone (MIBK) is effective for both HMF and furfural compounds. 5,6,9 Other possibility for identifying efficient solvents for extraction is via computational methods.…”

“…Recent experimental studies have investigated different solvents for extraction [7][8][9][10] and some authors have suggested that 2-butanol and 2-butanone are effective for HMF, while methyl isobutyl ketone (MIBK) is effective for both HMF and furfural compounds. 5,6,9 Other possibility for identifying efficient solvents for extraction is via computational methods. Thus, Sandler and co-workers 11 have used the COSMO-SAC method to investigate the ability of several linear and branched alcohols to extract HMF from aqueous solution and have found that the method produces reasonable partition coefficients.…”