Calorimetric Properties and Solubility in Five Pure Organic Solvents of N-Methyl- d -Glucamine (Meglumine)

The solid-liquid solubility of the title compound has been measured by a gravimetric method in five pure organic solvents over the temperature range (283 to 323) K. The melting temperature and associated enthalpy of fusion have been determined by differential scanning calorimetry (DSC), and the heat capacity of the solid and the melt have been determined over a range of temperatures by means of temperature-modulated DSC. Melting data and the extrapolated difference in heat capacity between the melt and the solid have been used to calculate the Gibbs energy, enthalpy, and entropy of fusion and the ideal solubility from below ambient temperature to the melting point. On the basis of estimated activity coefficients at equilibrium, solutions in all the five solvents are shown to exhibit positive deviation from Raoult's law. The highest mole fraction solubility is observed in methanol, and all van't Hoff solubility curves are nonlinear. Solubility data is well correlated by a recently proposed semiempirical regression model.