Determination and correlation of solubility data and dissolution thermodynamic data for 2-acrylamido-2-methyl-1-propane-sulfonic acid in seven pure solvents

The solubility of 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) in seven pure solvents, methanol, ethanol, 2-propanol, 1-butanol, isopentanol, acetone, and ethyl acetate, in the temperature range between 283.15 and 328.15 K at atmospheric pressure (101.3 kPa) is reported in this paper. The solubility of 2-acrylamido-2-methyl-1-propane-sulfonic acid increases with temperature in all selected solvents. The van’t Hoff equation, modified Apelblat equation, Wilson model, and λh model were applied to correct the solubility data. The results show that the modified Apelblat equation fits the best, with an average relative deviation of less than 3.70%. The mixing properties, such as Gibbs free energy, enthalpy and entropy of AMPS, were calculated based on the van’t Hoff equation. The dissolution process of AMPS in all solvents selected is endothermic, non-spontaneous and enthalpy-driven.