Journal of Chemical Thermodynamics, Vol.55, 75-78, 2012
Solubility of gallic acid in liquid mixtures of (ethanol plus water) from (293.15 to 318.15) K
The solubility of gallic acid in (water + ethanol) binary solvents was determined from (293.15 to 318.15) K at atmospheric pressure using a thermostatted reactor and UV/vis spectrophotometer analysis. The effects of binary solvents composition and temperature on the solubility were discussed. It was found that gallic acid solubility in (water + ethanol) mixed solvents presents a maximum-solubility effect. Two empirical equations were proposed to correlate the solubility data. The calculated solubilities show good agreement with the experimental data within the studied temperature range. Using the experimentally measured solubilities, the thermodynamic properties of dissolution of the gallic acid such as Gibbs energy (Delta(sol)G degrees), molar enthalpy of dissolution (Delta H-sol degrees), and molar entropy of dissolution (Delta S-sol degrees) were calculated. (C) 2012 Elsevier Ltd. All rights reserved.