Thermodynamic study of solubility for 2-amino-4-chloro-6-methoxypyrimidine in twelve organic solvents at temperatures from 273.15 K to 323.15 K

Abstract

The solubility of 2-amino-4-chloro-6-methoxypyrimidine in methanol, ethanol, chloroform, toluene, ethyl acetate, acetonitrile, n-propanol, acetone, N,N-dimethylformamide, isopropanol, 1,4-dioxane and ethyl benzene was obtained experimentally using the high-performance liquid chromatography analysis at temperatures ranging from (273.15 to 323.15)K under atmospheric pressure. The solubility of 2-amino-4-chloro-6-methoxypyrimidine in a fixed solvent increased with an increase in temperature. At a certain temperature, the mole fraction solubility in different solvents decreased according to the following order: N,N-dimethylformamide>dioxane>acetone>ethyl acetate>chloroform>(acetonitrile, n-propanol)>(ethanol, isopropanol)>methanol>toluene>ethyl benzene. Four models, modified Apelblat equation, λh equation, Wilson model and NRTL model were applied to correlate of the experimental solubility results. The largest values of relative average deviation and root-mean-square deviation acquired by the four models are 1.21% and 10.71×10−4, respectively. The modified Apelblat model is regarded as the best one for describing the experimental values. Furthermore, the mixing Gibbs energy, mixing enthalpy, and mixing entropy, activity coefficient and reduced excess enthalpy at infinitesimal concentration were obtained based on the mole fraction solubility. The mixing process of 2-amino-4-chloro-6-methoxypyrimidine in the selected solvents is discussed.