Modeling of thermodynamics properties of amino acid solutions by COSMO-SAC model

•The melting points and heat of fusions for various amino acid were determined by COSMO-SAC model.•Performance of the COSMO-SAC model were tested by considering amino acid solutions.•The electrolyte medium and pHs influence on solubility data were determined by considering COSMO-SAC model. The solubility and activity coefficients of various amino acids in pure solvents were calculated by the predictive COSMO-SAC model. To this end, pure solvents, mixed solvents, aqueous solutions at different pHs, aqueous salt solutions, and aqueous salt solutions at different pHs were studied. The average value of the logarithmic root mean square error (RMSE) for the solubility data was 1.112 for all systems including 678 binary systems, 1243 ternary systems, 72 aqueous salt solutions, and 259 aqueous solutions with pH variations. The calculated RMSEs for the activity coefficients and octanol/water partition coefficients were 0.55 and 1.60, respectively. The results of the COSMO-SAC model for the aqueous electrolyte solutions were consistent with the experimental data. The calculated solubility and activities revealed the negative impact of the hydrophobic nature of molecules on the accuracy of model predictions.