Solubility of N-phenylanthranilic acid in nine organic solvents from T = (283.15 to 318.15) K: Determination and modelling

Abstract

The solubility of N-phenylanthranilic acid in nine pure organic solvents including methanol, ethanol, acetone, acetonitrile, ethyl acetate, n-propanol, isopropanol, 1-butanol and toluene was determined experimentally by using the isothermal saturation method within the temperature range from (283.15 to 318.15)K under atmosphere pressure. For all the selected solvents, the solubility increased with a rise in temperature. In general, solubility followed the order from high to low in different solvents: acetone>ethyl acetate>1-butanol>n-propanol>ethanol>isopropanol>methanol>toluene>acetonitrile. The experimental solubility values for N-phenylanthranilic acid in these solvents was correlated by the modified Apelblat equation, λh equation, Wilson model and NRTL model. The largest value of root-mean-square deviation (RMSD) was 8.94×10−4, and of relative average deviation (RAD), 3.55%. For a specific solvent, the RAD value obtained with the modified Apelblat equation was smaller than those with the other models. By and large, the four thermodynamic models were all acceptable for the systems of N-phenylanthranilic acid in these solvents. In addition, the mixing properties of the solutions, including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were achieved. The solution process of N-phenylanthranilic acid was spontaneous and endothermic in the studied solvents. The solubility and modelling and thermodynamic studies would be helpful for the purification process of N-phenylanthranilic acid.