Measurement and correlation of the solubility of N-(phosphonomethyl)iminodiacetic acid in different organic solvents

The solubility of N-(phosphonomethyl) iminodiacetic acid (PMIDA) in methanol, ethanol, isopropanol, 1-butanol, 1-pentanol, 1-hexanol, acetone, methylbenzene and ethyl acetate were measured over a temperature range from 293.15 to 343.15 K under atmospheric pressure. The hypothetical enthalpy of fusion and melting temperature of PMIDA were estimated. The Scatchard–Hildebrand (SH) model, the Wilson model, the nonrandom two-liquid (NRTL) model and the universal quasi-chemical (UNIQUAC) 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 PMIDA was obtained based on the SH model.