Solubility determination and correlation of cyromazine in sixteen pure solvents and mixing properties of solutions

The solubility of cyromazine in the pure solvents (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, water, acetone, 2-propanol, isobutanol , 3-methyl-1-butanol and 2-butanol) at 283.15 K–323.15 K, cyromazine in the pure solvents (acetic acid and acrylic acid) at 293.15 K–333.15 K and cyromazine in the pure solvent of propanoic acid at 278.15 K–318.15 K. were measured by a laser dynamic method under atmospheric pressure. The experimental results show that the mole fraction solubility of cyromazine in the sixteen pure solvents decreased according to the following order: acrylic acid  > acetic acid > propanoic acid > methanol > ethanol ≈ water > 1-propanol > 1-butanol >1-pentanol >1-hexanol > 1-heptanol > 3-methyl-1-butanol ≈ (2-propanol, 2-butanol, isobutanol and acetone). In order to facilitate industrial application (to improve the purity of cyromazine by crystallization in industry) and other research studies, the experimental solubility data are correlated with the five thermodynamic models: modified Apelblat equation, λh equation, non-random two liquid (NRTL) model equation, Wilson model equation and van't Hoff equation. Moreover, the mixing Gibbs energy (Δ mix G ), mixing entropy (Δ mix S ), mixing enthalpy (Δ mix H ), activity coefficient ( γ 1 ∞ ${\gamma }_1^{\infty }$ ) at infinitesimal concentration and reduced excess enthalpy ( H 1 E , ∞ $H_1^{E,\infty }$ ) were obtained and the mixing process of cyromazine in the selected solvents are evaluated based on the Wilson model. The relatively close values of γ 1 ∞ ${\gamma }_1^{\infty }$ and γ 1 indicated that the cyromazine -selected solvents solution systems are not highly non-ideal.