Thermal properties and solubility of methyl α-d-glucopyranoside in methanol at different temperatures

Heat capacity of methyl α- d -glucopyranoside (α-MeG) was measured by differential scanning calorimetry at the temperatures ranging from 298.15 to 513.15 K. Melting point, enthalpy and entropy of fusion, enthalpy H T – H 298.15 K , and entropy S T -S 298.15 K were determined. Thermal decomposition of α-MeG was investigated using thermogravimetric analysis under pure nitrogen atmosphere. Ozawa-Flynn-Wall and ASTM models were used to calculate the activation energy and pre-exponential factor. Solubilities of α-MeG in methanol were measured within the temperature range of 293.15–318.15 K by using a synthetic method under atmospheric pressure. The modified Apelblat, λh , Wilson and NRTL models were applied to correlate the experimental data. The calculated results show good agreement with the experimental data and Wilson model is slightly more accurate than modified Apelblat, λh and NRTL models. The dissolution enthalpy, entropy, and Gibbs free energy were calculated by the Van't Hoff equation. The excess enthalpy of the solution can be evaluated by the λh model.