Determination and Correlation of Solubilities of (S)-Indoline-2-carboxylic Acid in Six Different Solvents from (283.15 to 358.15) K

The solubilities of (S)-indoline-2-carboxylilc acid (SIn2CA) in six pure solvents including water, methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol were determined from (283.15 to 358.15) K at atmospheric pressure using the synthetic method. The solubility was determined by a laser monitoring observation technique and found to increase with the rise of temperature. The experimental solubilities were correlated by the modified Apelblat and λh (Buchowski) equations with the relative deviation less than 3.65% with the modified Apelblat equation and less than 0.023% with the λh equation. Thermodynamic functions of the solution of SIn2CA in different solvents including apparent dissolution enthalpy and entropy were obtained by van’t Hoff equation, and the apparent dissolution Gibbs free energy change was also calculated.