Experimental and correlated solid–liquid equilibrium data of quizalofop-p-ethyl + CH3OH + H2O and quizalofop-p-ethyl + CH3CH2OH + H2O

Highlights: • The solubility of quizalofop-p-ethyl in different methanol + water and ethanol + water was was determined and correlated. • Experimental data were well correlated with the the modified Apelblat, λh and Jouyban-Acree model. • The strength of hydrogen bonds of between quizalofop-p-ethyl and methanol + water and ethanol + water was calculated. Quizalofop-p-ethyl (C₁₉H₁₇ClN₂O₄) is a widely used herbicide for controlling annual and perennial grass weeds in broad-leaved agricultural crops. The solid–liquid phase equilibrium of quizalofop-p-ethyl in binary solvents (methanol + water and ethanol + water) was measured by using a gravimetric method from (293 to 322) K at atmospheric pressure. The results indicated that the solubility of quizalofop-p-ethyl increases with increasing temperature and decreases with increasing mass fraction of water in binary solvents. Solubility of quizalofop-p-ethyl in methanol + water and ethanol + water range from 0.0000158 to 0.0113177 and 0.000285–0.0157060 in rang of 293 to 322 K at mass fraction of water 0.10–0.60, respectively. The modified Apelblat model, λh model and Jouyban-Acree model were applied to correlate the experimental data. The strength of intermolecular hydrogen bonds were calculated by optimizing the complexes between quizalofop-p-ethyl and solvents with the B3LYP theoretic method and the 6–31 + G(d,p) basis set, which showed the bent OH···O and OH···N was −31471.040 and −33892.903 kJ·mol⁻¹, respectively. The calculated dissolution enthalpy and entropy of quizalofop-p-ethyl in the binary solvents were positive, which indicated that the process is endothermic and increased randomness.