Solid–liquid phase equilibrium of glyphosate in selected solvents

Solid–liquid equilibrium (SLE) data for the glyphosate in methanol, ethanol, n-propanol, 2-propanol, acetone, benzene and ethyl acetate, and aqueous sodium chloride solutions were measured with a temperature range from (283 to 352) K. The hypothetical enthalpy of fusion and melting temperature of glyphosate were estimated. The Wilson model, the nonrandom two-liquid (NRTL) model, the universal quasi-chemical (UNIQUAC) model, and the Scatchard–Hildebrand (SH) model were applied to correlate the solid–liquid equilibrium. It is shown that the Wilson model can give better results than NRTL and UNIQUAC model. The solubility parameter of glyphosate was obtained based on the SH model. In aqueous sodium chloride solutions, the solubility of glyphosate increases with the molality of sodium chloride increasing. The system of glyphosate + sodium chloride + water is found to exhibit a synergistic effect.