Solubility modelling and dissolution properties of 5-phenyltetrazole in thirteen mono-solvents and liquid mixtures of (methanol + ethyl acetate) at elevated temperatures. (September 2017) - Chen, Gaoquan
Graphical abstract: Highlights: Solubility of 5-phenyltetrazole in thirteen neat solvents were determined. Solubility of 5-phenyltetrazole in (methanol + ethyl acetate) mixtures were measured. Solubility data were correlated and calculated by using different models. Preferential solvation in (methanol + ethyl acetate) were discussed. Abstract: The solid-liquid phase equilibrium of 5-phenyltetrazole in thirteen mono-solvents including methanol, ethanol, n-propanol, isopropanol, acetone, 2-butanone, acetonitrile, ethyl acetate, toluene, 1, 4-dioxane, cyclohexane, dimethyl sulfoxide (DMSO), N, N -dimethyl formamide (DMF) and liquid mixtures (methanol + ethyl acetate) were obtained experimentally via the isothermal saturation method within the temperatures from (283.15 to 318.15) K under about 101.2 kPa. It was intuitive to notice that the solubility values of 5-phenyltetrazole in studied solvents increased with increasing temperature. The descending order of the solubility data in different mono-solvents was as follows: DMSO > DMF > acetone > methanol > (ethanol, 2-butanone) > isopropanol > n -propanol > 1, 4-dioxane > ethyl acetate > acetonitrile > toluene > cyclohexane. For the binary solvent mixtures of (methanol + ethyl acetate) with given initial compositions, the maximum solubility was observed in neat methanol. The solubility data in mono-solvents were correlated and calculated by using the modified Apelblat equation and the Buchowski-Książczak λh equation; and in the binary solvent mixtures, by three cosolvency models. The largest values of RAD and RMSD were 1.25% and 4.83 × 10 −4, respectively. The apparent dissolution enthalpy was positive, illustrating that the dissolution process of 5-phenyltetrazole was endothermic. Finally, the preferential solvation parameters ( δx 1, 3 ) of 5-phenyltetrazole in (methanol + ethyl acetate) mixtures at (293.15–313.15) K were derived by using the inverse Kirkwood–Buff integrals method. The δx 1, 3 values were positive in methanol-rich compositions and negative in the other regions.