Solubility, dissolution enthalpy and entropy of l-glutamine in mixed solvents of ethanol + water and acetone + water

The solubilities of l-glutamine in mixed solvents (ethanol + water, acetone + water) were determined at temperatures between 278 K and 313 K. The solubilities of l-glutamine in mixed solvents (water + ethanol, water + acetone) are a function of temperature, increasing with an increase in temperature. Pure water has a high dissolving power. The experimental data were correlated with the Apelblat model. The calculated values of Apelblat model were found to show a fine representation of the experimental data. Then the dissolution enthalpy and entropy of l-glutamine were predicted from the solubility data using van’t Hoff equation. The dissolution enthalpy and entropy of l-glutamine in water predicted from the solubility data is less than that in mixed solvents.

► The solubilities of l-glutamine in mixed solvents (ethanol + water, acetone + water) were measured.
► It increases with an increase in temperature.
► Pure water has a high dissolving power.
► The calculated solubility sets a good coherence with the experimental values.
► The dissolution enthalpy and entropy were predicted using van’t Hoff equation.