Solubility Measurement and Thermodynamic Properties of Atrazine in 13 Pure Solvents from 283.15 to 323.15 K

The solubility of the herbicide atrazine was measured in 13 pure solvents (2-butanol, ethyl formate, methyl acetate, n-butyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, o-xylene, m-xylene, diisopropyl ether, acetonitrile, tetrahydrofuran, acetone) using the gravimetric method over a temperature range of 283.15 to 323.15 K at 0.1 MPa. The results demonstrated a remarkable increase in atrazine solubility with rising temperature, showing enhancements of 2 to 5-fold depending on the solvent. The experimental solubility data were well-fitted to five mathematical models: the modified Apelblat model, lambda h equation, van't Hoff equation, Wilson model, and NRTL model, where the Wilson model showed the best correlation. Furthermore, the thermodynamic analysis revealed that the mixing processes of atrazine and solvent are spontaneous and entropy driven. The solubility variations were analyzed in relation to the solvents' physicochemical properties, including polarity, hydrogen bond donor and acceptor abilities, and cohesive energy density. Atrazine exhibited lower solubility in highly polar solvents like acetonitrile, while demonstrating higher solubility in less polar solvents such as e n-butyl acetate.