Measurement and Correlation for Solubility of l‑Alanine in Pure and Binary Solvents at Temperatures from 283.15 to 323.15 K

The solubility of l-alanine in five binary systems water + methanol, water + ethanol, water + 1-propanol, water + 2-propanol, and water + acetone and 12 neat solvents (water, 1-butanol, methanol, 2-butanol, 2-methyl-1-propanol, 1-pentanol, 1-propanol, ethanol, 2-propanol, ethyl acetate, acetonitrile, and acetone) was determined by the gravimetrical method within the temperature range from 283.15 to 323.15 K under atmospheric pressure. The experimental results indicated that the solubility increased with increasing temperature and mole ratio of water in all investigated solvents and decreased with the rise of the mole fraction of five different organic solvents in the binary solvent systems. The order of l-alanine solubility in the selected pure solvents was water > 1-butanol > methanol ≈ 2-butanol > 2-methyl-1-propanol ≈ 1-pentanol ≈ 1-propanol ≈ ethanol > 2-propanol > ethyl acetate > acetonitrile > acetone. The solubility was mathematically represented by the modified Apelblat, Jouyban–Acree, and Apelblat–Jouyban–Acree models. All the models can be found to agree well with the data in the experiment.