Modeling the Solubility of Phenolic Acids in Aqueous Media at 37 °C

In this work, the solubility of vanillic, gallic, syringic, p-coumaric, ferulic and caffeic acids was determined at 37 & DEG;C under different conditions, namely pure water and two different ionic media, NaCl(aq) and NaClO4(aq), at different ionic strengths (i.e., 0.16, 0.50, 1.0, 2.0 and 3.0 M). The solubility in water of all the acids was found to be higher than that in both of the ionic media. Moreover, the solubility of hydroxycinnamic acids was lower than that of hydroxybenzoic acids. The activity coefficients of neutral species were calculated from these data; this knowledge is necessary when modeling the dependence of equilibrium constants on the ionic strength. Results obtained in this work can be useful for further studies regarding complex formation equilibria between these ligands and bioavailable metal cations.

Automated summary

In this study, the solubility of various acids was determined under different conditions, showing higher solubility in water compared to ionic media. The activity coefficients of neutral species were calculated from the data, providing important information for modeling equilibrium constants with ionic strength. Results obtained can be useful for further studies on complex formation equilibria between ligands and bioavailable metal cations.