Comment on “Measurement and Correlation of the Solubility of p-Coumaric Acid in Nine Pure and Water + Ethanol Mixed Solvents at Temperatures from 293.15 to 333.15 K”

Abstract

Experimental solubility measurements for p-coumaric acid dissolved in nine neat organic solvents and in binary aqueous-ethanol solvent mixtures are used to calculate solute descriptors for the monomeric form of the carboxylic acid based on the Abraham solvation parameter model. The solute descriptors once calculated are used to predict the solubility of p-coumaric acid in additional organic solvents in which the carboxylic acid is expected to exist predominantly in monomeric form.

Solid-liquid phase equilibrium of trans-cinnamic acid, p-coumaric acid and ferulic acid in water and organic solvents: Experimental and modelling studies

“…The authors estimated E through a group contribution model proposed by Platts et al [56], which allowed the calculation of different values for both monomeric and dimeric forms of the cinnamic acid, which is different from the methodology used in this work. It is relevant to mention that, as discussed by Bradley et al [8] and Acree et al [40], cinnamic acids might dimerize in less polar solvents, such as alkyl benzenes, chloroalkanes and nonpolar hydrocarbons. As the set of solvents selected to correlate the parameters of solutes in both NRTL-SAC and Abraham models are composed by polar solvents, such as alcohols, ketones, esters and nitriles, the parameters obtained in this work are expected to provide reliable solubility predictions for systems where the solute is predominantly present in the monomeric form.…”

“…Regarding the solute descriptors, they can be estimated by multiple linear regression, using experimental solubility data. Estimations of the solute descriptors have been already reported for the monomeric and dimeric forms of trans-cinnamic acid [8] and for the monomeric form of p-coumaric acid [40], but no information was found for ferulic acid.…”

“…To the best of our knowledge, the Abraham solvation descriptors are reported for the first time for ferulic acid. Bradley et al [8] and Acree et al [40] have already applied the model to describe the SLE of the monomeric and dimeric forms of trans-cinnamic acid and the monomeric form of p-coumaric acid, respectively. In the first case, the authors considered the solubility data of trans-cinnamic acid in water and in 21 organic solvents along with water-solvent partition coefficient data of five systems.…”

“…Finally, to model the solid-liquid equilibria data, two semipredictive thermodynamic models were selected: (1) the semipredictive Nonrandom Two-Liquid Segment Activity Coefficient (NRTL-SAC) model proposed by Chen and Song [22] that was already used to describe the solubility of phenolic compounds in water and organic solvents [23e28]; (2) the Abraham solvation model [29e31] that has been applied to calculate the solubility of benzoic acid derivatives [28,32e39], and cinnamic acid derivatives [8,40]. To support the description of the solid-liquid equilibria, the melting properties of the pure solutes were measured by Differential Scanning Calorimetry (DSC) and solid phase studies were carried out by X-Ray Diffraction (XRD).…”

Solvent and temperature effects on the solubility of syringic, vanillic or veratric acids: Experimental, modeling and solid phase studies

“…Alternately, due to the high uncertainty of the melting enthalpies of the studied acids, the reference solvent approach (RSA) was combined with the NRTL-SAC model [32,34] under the same conditions as mentioned before. A third approach followed in this work was the application of the Abraham solvation model [35][36][37], which was already successfully employed to predict SLE for several substituted benzoic acids [38][39][40][41][42][43][44][45][46][47] in different organic solvents.…”