Browsing by Author "Fernandes, Luciano"
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- Solubility and solid phase studies of isomeric phenolic acids in pure solventsPublication . Vilas-Boas, Sérgio M.; Brandão, Paula; Martins, Mónia A.R.; Silva, Liliana P.; Schreiner, Tatiana B.; Fernandes, Luciano; Ferreira, Olga; Pinho, SimãoThe solubilities of gallic, protocatechuic, gentisic or α-resorcylic acids were measured in nine pure solvents (water, methanol, ethanol, 1-propanol, 2-propanol, 2-butanone, ethyl acetate, acetonitrile and dimethylformamide) at 298.15 K and 313.15 K, using the analytical isothermal shake-flask method. Additionally, solid phase studies of the selected phenolic acids were carried out using differential scanning calorimetry (DSC) and X-ray diffraction (XRD), giving access to important data on melting properties as well as on the structure of the solid phase before and after the dissolution. The NRTL-SAC model coupled to the reference solvent approach (RSA) were applied to correlate the solubility data in a set of seven solvents and, after used to predict the solubility in 1-propanol and dimethylformamide. Average relative deviations (ARD) between 28 and 40% for the correlation and between 16 and 59% for the predictions were obtained. These values are within the order of magnitude usually found for such type of semi-predictive models, using a limited set of data.