Solubility of (S)-3-(Aminomethyl)-5-Methylhexanoic Acid in Pure and Binary Solvent Mixtures

The solubility of (S)-3-(aminomethyl)-5-methylhexanoic acid in both 2-propanol and water and methanol and water mixtures, as well as in pure solvents, is reported across the temperature range of 283.15–338.15 K, as determined gravimetrically under atmospheric conditions. The experimental data is correlated using the empirical Apelblat and (CNIBS)/Redlich–Kister equations to describe the influence of temperature and solvent composition on solubility, respectively. A maximum solubility is observed between x2/(x2 + x3) = 0.15 and x2/(x2 + x3) = 0.25 for 2-propanol and water mixtures and between x2/(x2 + x3) = 0.35 and x2/(x2 + x3) = 0.5 for methanol and water mixtures. The solubility data is then used to estimate the binary activity coefficient using the Wilson and NRTL activity coefficient models, as well as the coefficients of the Jouyban–Acree empirical solubility model, as a function of temperature and composition. The goodness of fit is determined using the mean square error as a metric in which the Jouyban–Acree model provides the best fit to the solubility data. The modified Apelblat equation is also used to calculate enthalpies of solution under standard conditions.