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Aqueous solubility of some natural phenolic compounds / Fatima L. Mota in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5182–5189 Titre : Aqueous solubility of some natural phenolic compounds Type de document : texte imprimé Auteurs : Fatima L. Mota, Auteur ; António J. Queimada, Auteur ; Simao P. Pinho, Auteur ; Eugénia A. Macedo, Auteur Année de publication : 2008 Article en page(s) : p. 5182–5189 Note générale : Bibliogr. p. 5188-5189 Langues : Anglais (eng) Mots-clés : Hydroxybenzoic  acids;  Phenylpropenoic  acids;  Shake-flask  method Résumé : In this work, the aqueous solubilities of two hydroxybenzoic acids (gallic and salicylic acid) and three phenylpropenoic acids (trans-cinnamic, ferulic, and caffeic acids) are addressed. Measurements were performed, as a function of temperature, between 288.15 and 323.15 K, using the shake-flask method for generating the saturated aqueous solutions, followed by compositional analysis by spectrophotometric and gravimetric methods. The pH values of the saturated aqueous solutions were measured by potentiometry. Additional thermodynamic properties, which are fundamental for a better understanding of the solubilization process, as well as necessary for the modeling studies, such as melting temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC). Apparent acid dissociation constants (Ka) were obtained by potentiometry titration. The measured data were modeled with the cubic-plus-association (CPA) equation of state (EoS). This EoS is applied, for the first time, for multifunctional associating molecules, and the results indicate that it can adequately be used to represent the measured and other literature data with satisfactory accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071452o [article] Aqueous solubility of some natural phenolic compounds [texte imprimé] / Fatima L. Mota, Auteur ; António J. Queimada, Auteur ; Simao P. Pinho, Auteur ; Eugénia A. Macedo, Auteur . - 2008 . - p. 5182–5189. Bibliogr. p. 5188-5189 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5182–5189 Mots-clés : Hydroxybenzoic  acids;  Phenylpropenoic  acids;  Shake-flask  method Résumé : In this work, the aqueous solubilities of two hydroxybenzoic acids (gallic and salicylic acid) and three phenylpropenoic acids (trans-cinnamic, ferulic, and caffeic acids) are addressed. Measurements were performed, as a function of temperature, between 288.15 and 323.15 K, using the shake-flask method for generating the saturated aqueous solutions, followed by compositional analysis by spectrophotometric and gravimetric methods. The pH values of the saturated aqueous solutions were measured by potentiometry. Additional thermodynamic properties, which are fundamental for a better understanding of the solubilization process, as well as necessary for the modeling studies, such as melting temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC). Apparent acid dissociation constants (Ka) were obtained by potentiometry titration. The measured data were modeled with the cubic-plus-association (CPA) equation of state (EoS). This EoS is applied, for the first time, for multifunctional associating molecules, and the results indicate that it can adequately be used to represent the measured and other literature data with satisfactory accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071452o

Solubility of flavonoids in pure solvents / Olga Ferreira in Industrial & engineering chemistry research, Vol. 51 N° 18 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 18 (Mai 2012) . - pp. 6586-6590 Titre : Solubility of flavonoids in pure solvents Type de document : texte imprimé Auteurs : Olga Ferreira, Auteur ; Simao P. Pinho, Auteur Année de publication : 2012 Article en page(s) : pp. 6586-6590 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Solubility Résumé : The fast and efficient selection of food-approved solvents is required for a growing number of flavonoids that are continuously being tested for their nutraceutical properties. Solid―Hquid equilibrium is an essential source of information for the design of extraction, precipitation, or crystallization processes in the food industry. In this context, the nonrandom two-liquid segment activity coefficient thermodynamic model showed to be an appropriate tool to represent the solubility of several key flavonoids (apigenin, genistein, hesperetin, luteolin) in pure solvents, suggesting its ability to predict solubility in solvents not considered during the correlation procedure. For substances with unknown melting properties the reference solvent approach was successfully applied. Additionally, new solubility data of S-hesperetin in the pure solvents acetone, ethanol, ethyl acetate, methanol, and acetonitrile was measured, between 25 and 40 °C, by the shake-flask method. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25867309 [article] Solubility of flavonoids in pure solvents [texte imprimé] / Olga Ferreira, Auteur ; Simao P. Pinho, Auteur . - 2012 . - pp. 6586-6590. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 18 (Mai 2012) . - pp. 6586-6590 Mots-clés : Solubility Résumé : The fast and efficient selection of food-approved solvents is required for a growing number of flavonoids that are continuously being tested for their nutraceutical properties. Solid―Hquid equilibrium is an essential source of information for the design of extraction, precipitation, or crystallization processes in the food industry. In this context, the nonrandom two-liquid segment activity coefficient thermodynamic model showed to be an appropriate tool to represent the solubility of several key flavonoids (apigenin, genistein, hesperetin, luteolin) in pure solvents, suggesting its ability to predict solubility in solvents not considered during the correlation procedure. For substances with unknown melting properties the reference solvent approach was successfully applied. Additionally, new solubility data of S-hesperetin in the pure solvents acetone, ethanol, ethyl acetate, methanol, and acetonitrile was measured, between 25 and 40 °C, by the shake-flask method. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=25867309

Thermodynamic modeling of several aqueous alkanol solutions containing amino acids with the perturbed-chain statistical associated fluid theory equation of state / Luísa A. Ferreira in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5498–5505 Titre : Thermodynamic modeling of several aqueous alkanol solutions containing amino acids with the perturbed-chain statistical associated fluid theory equation of state Type de document : texte imprimé Auteurs : Luísa A. Ferreira, Auteur ; Martin P. Breil, Auteur ; Simao P. Pinho, Auteur Année de publication : 2009 Article en page(s) : pp. 5498–5505 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : EoS  Amino  acids  Aqueous  solutions  Solubility Résumé : The perturbed-chain statistical associated fluid theory EoS was applied to model the solubilities of glycine, dl-alanine, l-serine, l-threonine, and l-isoleucine in pure water, pure alcohols (ethanol, 1-propanol, and 2-propanol) and in mixed solvent systems. Three pure component nonassociating parameters for the amino acids were fitted to the densities, activity and osmotic coefficients, vapor pressures, and water activity of their aqueous solutions. The solubilities of amino acids in pure and mixed solvent systems were calculated on the basis of the phase equilibrium conditions for a pure solid and a fluid phase. The hypothetical melting properties of each amino acid were fitted, to accurately correlate the solubilities in pure water. Only one temperature independent binary parameter is required for each amino acid/solvent pair. The model can accurately describe the solubility of the amino acids in water, but the correlation for the solubility in pure alcohols was not so satisfactory. The solubility in mixed solvents (ternary systems) was predicted on the basis of the modeling of the solubility in pure solvents, without any additional fitting of the parameters, and the results achieved were reasonable. Fitting the binary parameter for the pair amino acid/alcohol not to the solubility in pure alcohol, but to the solubility in the mixed solvent system, the description of the solubility in the mixed solvent systems was clearly improved and the results were in fair agreement with the experimental data for all mixture compositions. The results showed a global root-mean-square deviation in mole fraction of 0.0032 for correlation and 0.0070 for prediction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801567w [article] Thermodynamic modeling of several aqueous alkanol solutions containing amino acids with the perturbed-chain statistical associated fluid theory equation of state [texte imprimé] / Luísa A. Ferreira, Auteur ; Martin P. Breil, Auteur ; Simao P. Pinho, Auteur . - 2009 . - pp. 5498–5505. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5498–5505 Mots-clés : EoS  Amino  acids  Aqueous  solutions  Solubility Résumé : The perturbed-chain statistical associated fluid theory EoS was applied to model the solubilities of glycine, dl-alanine, l-serine, l-threonine, and l-isoleucine in pure water, pure alcohols (ethanol, 1-propanol, and 2-propanol) and in mixed solvent systems. Three pure component nonassociating parameters for the amino acids were fitted to the densities, activity and osmotic coefficients, vapor pressures, and water activity of their aqueous solutions. The solubilities of amino acids in pure and mixed solvent systems were calculated on the basis of the phase equilibrium conditions for a pure solid and a fluid phase. The hypothetical melting properties of each amino acid were fitted, to accurately correlate the solubilities in pure water. Only one temperature independent binary parameter is required for each amino acid/solvent pair. The model can accurately describe the solubility of the amino acids in water, but the correlation for the solubility in pure alcohols was not so satisfactory. The solubility in mixed solvents (ternary systems) was predicted on the basis of the modeling of the solubility in pure solvents, without any additional fitting of the parameters, and the results achieved were reasonable. Fitting the binary parameter for the pair amino acid/alcohol not to the solubility in pure alcohol, but to the solubility in the mixed solvent system, the description of the solubility in the mixed solvent systems was clearly improved and the results were in fair agreement with the experimental data for all mixture compositions. The results showed a global root-mean-square deviation in mole fraction of 0.0032 for correlation and 0.0070 for prediction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801567w