Density, viscosity, and speed of sound were measured for dimethyl sulfoxide (DMSO) + tri-n-butyl phosphate (TBP) mixtures at atmospheric pressure (0.10 MPa) over the full composition range and temperatures from 298.15 to 323.15 K. The mixtures exhibit pronounced structure-breaking behavior, with excess molar volumes reaching positive maxima of 1.05–1.07 cm3·mol–1 near a TBP mole fraction of ≈0.45. Viscosity deviations show positive peaks between 0.9 and 1.7 mPa·s, while isentropic compressibility deviations remain positive across all temperatures. Negative speed of sound deviations, reaching −300 m·s–1, further indicate weakened intermolecular networks compared to the pure components. FTIR spectra reveal composition-dependent shifts of 5–12 cm–1 in the S═O and P═O stretching bands, consistent with weak hydrogen bonding and dipole–dipole interactions. Density functional theory (DFT) calculations support formation of a stabilized TBP–DMSO adduct, showing short intermolecular contacts, charge redistribution, and reduced HOMO–LUMO gaps, consistent with enhanced polarity upon mixing. Experimental data were correlated using the Jouyban–Acree model, while the PC-SAFT equation of state reproduced liquid densities with an overall average relative deviation (ARD) of 0.08%. In addition, new interaction parameters for the (CH2)3PO–DMSO pair were computed and applied in group-contribution-based predictive models (UNIFAC-VISCO and UNIFAC-THERMO), yielding viscosity prediction ARDs of 2.7% and 2.4%, respectively.

Biobutanol is a superior biofuel alternative, but its recovery from acetone-butanol-ethanol (ABE) fermentation is inefficient due to azeotrope formation and high energy costs. This study investigates fructose-induced sugaring-out for phase separation and breaking the azeotrope, optimizing ABE recovery by analyzing the effects of sugar concentration and temperature. The results demonstrate efficient phase separation, with butanol recovery reaching 93.1%, acetone recovery at 66.0%, ethanol recovery at 59.1%, and water removal at 92.3%. Increasing fructose concentration enhances water exclusion and phase separation, while temperature variations play a secondary role compared to fructose concentration, only affecting separation efficiency at lower sugar concentrations. The findings highlight the dominant role of fructose-induced sugaring-out in phase formation and its potential for optimizing biofuel recovery. This method offers a highly efficient and tunable strategy for solvent recovery and water removal in biorefinery applications.

The mole fraction solubility of Isomalt in five binary solvent systems (water + methanol, ethanol, 1-propanol, isopropanol, tert-butanol) was determined via the gravimetric method at atmospheric pressure and 283.15–323.15 K. Solubility increased with rising temperature and water molar fraction, following the order: water + methanol > water + ethanol > water +1-propanol > water + isopropanol > water + tert-butanol, with solubility curve intersections indicating varying temperature sensitivities. Liquid–liquid phase separation occurred in water +1-propanol/isopropanol/tert-butanol at high water mole fractions. Four thermodynamic models (modified Apelblat, van’t Hoff, λh, Jouyban–Acree van’t Hoff) yielded excellent fits (ARD < 10%, RMSD < 0.1%), with the modified Apelblat model being best correlation. Hansen solubility parameter analysis showed solubility was governed by hydrogen-bonding parameters (Δδh) and total solubility parameter (Δδ̅). Hirshfeld surface analysis (HS) and radial distribution function (RDF) simulations confirmed hydrogen bonding as the dominant solute–solvent/solvent–solvent interaction. Thermodynamic calculations based on the van’t Hoff equation confirmed that the dissolution process is endothermic and entropy-driven. These findings provide comprehensive solubility data and mechanistic insights, supporting future research and applications of isomalt in alcoholic solutions.

Surfactants are widely employed across numerous applications due to their amphiphilic nature, which drives aggregate formation and enables the solubilization of hydrophobic compounds in aqueous solutions once the critical micelle concentration (CMC) is exceeded. In this work, we present a holistic modeling approach that considers both aggregation equilibria as well as phase equilibria in ternary systems of water, hydrophobic solutes (“oil”), and surfactants. For that purpose, PC-SAFT is incorporated into a novel mixed-aggregate formation model. Micellar solubilization effects are described by accounting for the formation of mixed oil-surfactant aggregates. Consequently, our model is based on a continuous distribution along all possible compositions and sizes of the mixed aggregates while calculating their equilibrium geometries. Our approach, for the first time, enables quasi-quantitative predictions of liquid–liquid equilibria in water–oil–surfactant systems. It accurately captures the sharp increase in oil solubility at surfactant concentrations just above the CMC and captures the influence of surfactant polarity on the maximum solubilization capacity for various hydrophobic solutes in very good agreement with experiments. Our methodology is validated for polyethoxylated alkyl ethers (CiEj) as surfactants and for alkanes and alkenes as example oil components, with the predicted binodal curves closely matching experimental LLE data.

Data on the apparent and standard partial molar volumes, Vø,2 and V¯2o(≡V¯ϕ,2∞), as well as the standard partial molar expansibilities, E¯p,2o, of N,N-dimethylglycoluril-N’-aminoisobutyric acid (DMGU-AIBA) in water were derived from density measurements of the corresponding aqueous solutions between 278.15 and 318.15 K and at ambient pressure. The uncertainty in density experiments did not exceed 0.10 kg m–3, and the solution molality for the aqueous DMGU-AIBA ranged from 0.002 to 0.06 mol·kg–1. Using the previously obtained results, it was established that the N’-alkyl-chain isomerization of N,N-dimethylglycoluril-aminobutyric acid (DMGU-ABA) as a solute in water, to form DMGU-AIBA, leads to squeezing of the structure packing of the formed “hydration complex”. This effect, being increasingly pronounced with rising temperature, is supposed to be due to a change in the solute–solvent interaction balance, against the background of an increase in the effect of solvent electrostriction near the solute molecule. It was concluded that the decisive role in the hydration of amino acid glycoluril derivatives belongs to hydrophilic effects, associated mainly with heterocomponent interactions through proton-donating/-accepting pharmacophore moieties, despite partial dissociation of DMGU-AIBA and DMGU-ABA in the aqueous medium.

2,2′-Bis(2-hydroxyethoxy)-1,1′-binaphthalene (BHB), a key optical polymer precursor, faces purification challenges, while its solubility behavior in binary solvents remains underexplored. In this work, the solubility behavior of BHB Form B was systematically investigated in four binary solvent systems (ethyl acetate + toluene, acetone + n-propanol, methyl acetate + n-butanol, and ethyl formate + i-propanol) across 283.15–323.15 K under ambient pressure. Experimental results showed that solubility increased with the temperature at fixed solvent compositions. Solubility initially increased and subsequently decreased with solvent compositions at constant temperatures, confirming the cosolvency effect. The experimental solubility data were well correlated using the modified Apelblat equation, NRTL model, CNIBS/R–K model, and Apelblat–Jouyban–Acree model, with the CNIBS/R–K model providing the best fitting performance. Solvation free energy further demonstrated that enhanced solute–solvent interactions contribute to the cosolvency effect. These findings provide valuable insight into optimizing crystallization processes in the industrial production of high-purity BHB.

Solubility still plays an important role in the field of drug development, purification, absorption, and delivery. In this work, the diclofenac (DIC) solubility in 1,4-dioxane, acetone, 2-butanone, acetonitrile, ethyl acetate, cyclohexane, methanol, ethanol, 1-propanol, 1-butanol, 2-propanol, water, and ethanol/acetone + water was determined using the isothermal saturation method at 278.15–318.15 K. The solubility regularity, solvent effect, solvation behavior, and model correlation were discussed. DIC solubility increased with rising temperature and exhibited different rates of increase in various solvents (or cosolvent compositions). The analysis indicated that DIC solubility showed a strong dependence on the solvent polarity, cohesive energy density, and viscosity. The solvent effect quantified by the Kamlet and Taft linear solvation energy relationship (KAT-LSER) model suggested that the contributions were 57.80 and 42.20% from solute–solvent interactions and solvent–solvent interactions, respectively. Thus, hydrogen bond acceptor (HBA) interactions and nonspecific dipolarity and polarizability dominated DIC dissolution. Afterward, solvation behavior analysis revealed positive δ values, suggesting that local ethanol/acetone was enriched around the DIC molecules. This demonstrates that DIC was preferentially solvated locally by ethanol/acetone. Additionally, model correlation revealed that the highest observed relative average deviation and root-mean-square deviation were 3.10% and 2.91 × 10–4, respectively. Consequently, the Apelbat, λh, Jouyban–Acree, and Apelbat–Jouyban–Acree models can accurately correlate the DIC solubility data.