Percorrer por autor "Benfica, Jordana"
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- Exploring the role of temperature on hydrotropyPublication . Abranches, Dinis O.; Soares, Bruna P.; Cordova, Isabella Weber; Benfica, Jordana; Ferreira, Olga; Pinho, Simão; Coutinho, João A.P.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).
- Unveiling the mechanism of hydrotropy: Evidence for water-mediated aggregation of hydrotropes around the solutePublication . Abranches, Dinis O.; Benfica, Jordana; Soares, Bruna de Paula; Leal-Duaso, Alejandro; Sintra, Tânia E.; Pires, Elísabet; Pinho, Simão; Shimizu, Seishi; Coutinho, João A.P.A recent proposal attributes the origin of hydrotropy to the water-mediated aggregation of hydrotrope molecules around the solute. Experimental evidence for this phenomenon is reported for the first time in this work, using 1H-NMR. A new computational technique to quantify apolarity is introduced and is used to show that apolarity of both solute and hydrotrope is the driving force of hydrotropy. This journal is
- What is better to enhance the solubility of hydrophobic compounds in aqueous solutions: eutectic solvents or ionic liquids?Publication . Ferreira, Olga; Silva, Liliana P.; Almeida, Heloísa H.S.; Benfica, Jordana; Abranches, Dinis O.; Pinho, Simão; Coutinho, João A.P.The solubilities of benzoic acid, (S)-hesperetin, and L-tryptophan in aqueous solutions of ionic liquids (choline glycolate and choline malonate) and the analogous eutectic solvents (choline chloride:glycolic acid and choline chloride:malonic acid) were studied. It is shown that while ionic liquids (IL) and eutectic solvents (ES) were able to increase the solubility of all compounds studied in aqueous solution, ionic liquids were much more efficient for neutral and acidic compounds, while eutectic solvents showed a better performance for the alkaline substances. The results reported here show that the solubility enhancement is related, in the first instance, to the pH of the aqueous solution, which is the dominant effect on the increase in solubility and the main parameter that must be taken into account when selecting a co-solvent to successfully achieve the solubilization of ionizable hydrophobic biomolecules in aqueous solution. In addition, a hydrotropy mechanism was identified when the pH effect was removed, supporting the idea that ionic liquids and eutectic solvents behave as hydrotropes in aqueous solutions. The results here reported show that rather than a focus on the type of solvents (IL vs. ES), the molecular mechanisms such as speciation and co-solvation/hydrotropy, which in some cases may have complementary and synergetic effects, are the parameters that must be addressed in the design or selection of the best solubility enhancer.