This work addresses the effect of chaotropic anions (thiocyanate and tosylate) on the solubility of glycine, L-leucine, L-phenylalanine, and L-aspartic acid in aqueous solutions at 298.2 K. The salts used were NaSCN, KSCN, NH4SCN, and NaC7H7SO3 (sodium tosylate), with salt concentrations ranging from 0 to 2 molal. The pH of the saturated solutions was registered, and solid-phase studies were also performed. All the thiocyanate salts and sodium tosylate induced a salting-in effect, except in the systems composed of glycine in aqueous sodium tosylate solutions at 0.5 and 1 molal. For L-leucine, L-phenylalanine, and L-aspartic acid the salting effect of anions followed the order tosylate− > SCN− > NO3- > Cl−, in good agreement with the behavior predicted by the Hofmeister series. Differently, the relative solubility of glycine in aqueous nitrate solutions was higher than in those containing thiocyanate, followed by the chloride and, closing the rank, the solutions containing the tosylate anion, suggesting that the solubility change in this case is achieved by a different mechanism.

Aqueous solubility can be enhanced through hydrotropy, where an amphiphilic molecule (the hydrotrope) ag-gregates around the solute, boosting its solubility. To understand the impact of temperature on this phenomenon, the solubility of syringic acid was measured in aqueous solutions of different bio-based hydrotropes. Solubility curves were modelled using Gaussian processes, a powerful class of machine learning interpolators. This allowed for a thermodynamic analysis of excess solvation properties that was complemented using the COSMO-RS model. As expected, the absolute solubility of syringic acid increased with temperature. However, at low hydrotrope concentrations, this increase was not driven by interactions in the liquid phase. Thus, the solubility enhancement of syringic acid was found to be independent of temperature. Conversely, at high hydrotrope concentrations, increasing the temperature significantly decreased the solubility enhancement of the solute. These effects were interpreted considering different solubilization mechanisms, namely hydrotropy (low hydrotrope concentrations) and co-solvency (high hydrotrope concentrations).

Countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC) are efficient techniques to purify terpenoids from essential oils. These methods require suitable solvent systems for the partition between the two immiscible liquid phases. In this study, using the analytical shake-flask method, we measured the partition coefficients of three model monoterpenoids, namely carvone, eucalyptol and thymol, in 11 biphasic solvent systems, at 298.2 K. Moreover, the predictive COSMO-RS model was applied to represent the partition coefficients of data measured in this work and retrieved from the literature, the liquid–liquid equilibrium (LLE) data of three solvent families suitable for CCC/CPC separations (i.e., Arizona, Modified Arizona and Green Arizona) and the solute's partition coefficients in the three solvent families. RESULTS: The partition coefficients obtained for thymol and eucalyptol are the first partition data available in the literature. The obtained root mean square deviations (RMSDs) between the experimental and predicted partition coefficients (log basis) varied between 0.28 and 0.49. For LLE, RMSDs of 0.040 and 0.048 were achieved for the Arizona and Green Arizona families, respectively. CONCLUSION: The predictive COSMO-RS model describes the monoterpenoid partition coefficients and the LLE data of the solvent families well. The most favorable solvent systems to perform the separations were identified, showing that systems with low and intermediate-to-low polarities are the most promising options for separating the selected monoterpenoids from their natural matrices by CCC/CPC techniques.

In aqueous solutions containing electrolytes, ions influence both the solubility and the stability of biomolecules. However, inconsistencies across published data highlight the need for a critical review. To address this, a database was constructed on the solubility of glycine in electrolyte solutions spanning from 1996 to 2024, and the experimental data were critically evaluated. Gaussian Process (GP) models were implemented to analyze, predict, and validate solubility behavior. The GP model successfully captures salting-in and salting-out trends, along with specific ion effects reported in the literature. It also provides predictive uncertainty estimates that help identify potentially inconsistent data points or sets. This uncertainty-based analysis enables the reconciliation of conflicting datasets and helps prioritize new experimental measurements in regions where data are sparse or less reliable. By applying a data-filtering method that removes experimental points falling outside the uncertainty range of the model, the influence of inconsistent values is reduced. This results in a more robust model fit and improved prediction accuracy. Therefore, the GP establishes a quantitative foundation for consolidating the current knowledge on the solubility of glycine in saline solutions, identifying methodological inconsistencies in the literature.

This work explores the impact of solute conformers on the conductor-like screening model for real solvents (COSMO-RS) solubility predictions of vanillin and ethyl vanillin in water, short alcohols, and their mixed solvents. Two major conformers of these solutes and changes with solvent polarity were experimentally established by Raman spectroscopy and further confirmed by density functional theory calculations. The COSMO-RS predictions using the individual conformers show a poor description of the solubilities. Estimation with the COSMO-RS default conformer distribution gave better predictions and an intermediate behavior between the predictions obtained using each individual conformer. To further improve the description of the solubilities, the weight of each conformer was fitted to the experimental solid-liquid equilibrium data of the solute in a pure solvent at different temperatures. Better solubility predictions in ternary systems describing solubility maxima were found, suggesting a semipredictive approach to COSMO-RS. This method can predict the liquid-liquid oiling-out effect in the studied binary and ternary systems.

Artemisinin, a drug used to treat malaria, can be chemically synthesized or extracted from Artemisia annua L. However, the extraction method for artemisinin from biomass needs to be more sustainable while maintaining or enhancing its bioactivity. This work investigates the use of aqueous solutions of salts and ionic liquids with hydrotropic properties as alternative solvents for artemisinin extraction from Artemisia annua L. Among the investigated solvents, aqueous solutions of cholinium salicylate and sodium salicylate were found to be the most promising. To optimize the extraction process, a response surface method was further applied, in which the extraction time, hydrotrope concentration, and temperature were optimized. The optimized conditions resulted in extraction yields of up to 6.50 and 6.44 mg·g-1, obtained with aqueous solutions of sodium salicylate and cholinium salicylate, respectively. The extracts obtained were tested for their antimalarial activity, showing a higher efficacy against the Plasmodium falciparum strain compared with pure (synthetic) artemisinin or extracts obtained with conventional organic solvents. Characterization of the extracts revealed the presence of artemisinin together with other compounds, such as artemitin, chrysosplenol D, arteannuin B, and arteannuin J. These compounds act synergistically with artemisinin and enhance the antimalarial activity of the obtained extracts. Given the growing concern about artemisinin resistance, the results here obtained pave the way for the development of sustainable and biobased antimalarial drugs. © 2024 The Authors. Co-published by Zhejiang University and American Chemical Society.

The recently proposed category of type V deep eutectic solvents (DESs), composed only of non-ionic species, has attracted great interest in the literature. However, despite their importance in solvent design, measuring the solid−liquid equilibrium (SLE) diagrams of all possible type V DES precursor combinations is unfeasible. Therefore, a reliable computational tool must be found to estimate SLE phase diagrams and, thus, the melting points of type V DESs. In this work, a total of 134 different binary eutectic systems (1744 datapoints) were gathered from the literature, and the calculation capabilities and accuracy of three different models COSMO-RS, UNIFAC of Dortmund, and Group and Group-Interaction Contribution method (GGIC) were evaluated. UNIFAC and COSMO-RS were, by far, the best performing models, with average absolute deviations (AADs) of, respectively, 6.9 K for 94 systems and 7.4 K for 133 systems. Due to a lack of group interaction parameters, UNIFAC could only describe 94 systems, a severe disadvantage over COSMO-RS. Moreover, despite being able to describe all 134 systems, the GGIC model resulted in an AAD of 37 K. Finally, the effect of using the different parametrizations or multiple conformers in COSMO-RS predictions was also evaluated, and the validity of neglecting heat capacity terms when performing SLE calculations was verified.

The use of ionic liquid [emim][Tf2N] as an additive in polyethersulphone (PES) and nanosized silico-aluminophosphate-34 (SAPO-34) mixed matrix membrane was studied through the incorporation of different amounts of [emim][Tf2N] in the membrane composition, as presented in this work, varying from 10 to 40 wt%. Through gas permeation tests using CO2 andN2, the membrane composition containing 20 wt% [emim][Tf2N] led to the highest increase in CO2 permeability and CO2/N2 selectivity. The use of low concentrations of additive (10–20 wt%) promoted a state called antiplasticization; in this state, the permeability was even more regulated by the kinetic diameter of the species which, in this work, permitted achieving a higher CO2/N2 selectivity while increasing the CO2 permeability until an optimal condition. [emim][Tf2N] also promoted a better dispersion of SAPO-34 particles and an increase in the flexibility of the polymeric matrix when compared to a film with the same composition without [emim][Tf2N]. Moreover, the characterizations corroborated that the inclusion of [emim][Tf2N] increased the zeolite dispersion and improved the polymer/zeolite compatibility and membrane flexibility, characterized by a decrease in glass transition temperature, which helped in the fabrication process while presenting a similar thermal resistance and hydrophilicity as neat PES membrane, without affecting the membrane structure, as indicated by FTIR and a contact angle analysis.

Mixed matrix membranes (MMM) are heavily studied and the main concern by researchers is the difficulty to obtain a high selectivity membrane with low defects, mainly interfacial voids due to the poor interaction between polymer matrix and filler. The functionalization of zeolite surface in PolyEtherSulphone (PES)/ Silico-AluminoPhosphate-34 (SAPO-34) led to membranes with higher compati-bility. Recently, the use of ionic liquids in the particles surface to improve the gas permeability and separation efficiency has presented advanced results. Although, the cost and environmental issues on Ionic Liquids (ILs) still represent a limit to its use. The Deep Eutectic Solvents (DESs) present an alternative route to replace ILs, with low-cost and environmentally friend. This paper aims to study the potential use of choline chloride/urea, a DES mixture, in ratio 1:2, to replace ILs as a post-healing methodology, showing a 20% increase in CO2 permeability in PES membranes and 15% increase in CO2/N2 selectivity in PES/SAPO-34 membranes due to an increase in compatibility between polymer and zeolite promoted by the post-treatment using DES.

Mixed matrix membranes (MMM) are heavily studied and the main concern by researchers is the difficulty to obtain a high selectivity membrane with low defects, mainly interfacial voids due to the poor interaction between polymer matrix and filler. The functionalization of zeolite surface in Poly-EtherSulphone (PES)/Silico-AluminoPhosphate-34 (SAPO- 34) led to membranes with higher compatibility. Recently, the use of ionic liquids in the particles surface to improve the gas permeability and separation efficiency has presented advanced results. The aim of this work is to compare the separation efficiency of CO2 and N2 in permeance and selectivity criteria. The use of the ionic liquid (IL) [emim][Tf2N] showed an increase in selectivity and in CO2 permeance due to promoting a better separation of the dispersant in the polymeric matrix when compared to a film with the same composition without the IL treatment.