Jian Wang, Anli Xu, R. Xu
May 1, 2017
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0
Influential Citations
41
Citations
Journal
The Journal of Chemical Thermodynamics
Abstract
Abstract By using the isothermal saturation method, the solid-liquid equilibrium of 2-nitro- p -phenylenediamine in pure organic solvents of methanol, ethanol, n -propanol, isopropanol, N -methyl-2-pyrrolidone, acetonitrile, ethyl acetate, toluene and 1,4-dioxane and liquid mixture of ( N -methyl-2-pyrrolidone + methanol) was obtained experimentally at the temperatures ranging from (283.15 to 318.15) K under atmospheric pressure, and the solubility of 2-nitro- p -phenylenediamine in the selected solvents was determined by a high-performance liquid chromatography (HPLC). Within the studied temperature range, the 2-nitro- p -phenylenediamine solubility in mole fraction in these solvents increased with increasing temperature. The descending order of the mole fraction solubility in pure solvents was as follow: ( N -methyl-2-pyrrolidone, 1,4-dioxane) > ethyl acetate > acetonitrile > methanol > ethanol > n -propanol > isopropanol > toluene, and for the ( N -methyl-2-pyrrolidone + methanol) mixture with given initial composition, the mole fraction solubility of 2-nitro- p -phenylenediamine increased with increasing temperature and mass fraction of N -methyl-2-pyrrolidone. The values of solubility for 2-nitro- p -phenylenediamine in pure solvent were correlated and calculated with the modified Apelblat equation, λh equation, Wilson model and NRTL model; and in the binary solvent mixture of ( N -methyl-2-pyrrolidone + methanol), the Jouyban–Acree model, modified Apelblat–Jouyban–Acree model and Sun model. For the pure solvents, the largest values of the relative average deviation ( RAD ) and root-mean-square deviation ( RMSD ) obtained by the four models were 1.17% and 6.80 × 10 −4 , respectively; and for ( N -methyl-2-pyrrolidone + methanol) mixture, they were a larger, which were 3.59% and 19.12 × 10 −4 . In general, the selected thermodynamic models were all acceptable for describing the solubility behaviour of 2-nitro- p -phenylenediamine in the solvents. In addition, the mixing properties including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration ( γ 1 ∞ ) and reduced excess enthalpy ( H 1 E, ∞ ) were calculated for 2-nitro- p -phenylenediamine in pure solvents. Knowledge of the solubility and thermodynamic studies is essential in optimizing the purification process of 2-nitro- p -phenylenediamine.