Solubility study of m-aminobenzoic acid form III in different mono-solvents by thermodynamic analysis and molecular simulation

Abstract

The solid–liquid equilibrium behavior of m–aminobenzoic acid (m–ABA) form III in eleven mono–solvents (methanol, ethanol, n–propanol, isopropanol, n–butanol, methyl acetate, propyl acetate, butyl acetate, acetone, butanone and water) was investigated in the temperature from 283.15 K to 323.15 K. Solubility data were successfully described and correlated by four thermodynamic models, and all calculated ARD% values are lower than 5%. The thermodynamic functions of mixing were calculated and analyzed based on the NRTL model, and the results show that the mixing process is spontaneous and entropy–driving. The characteristics of m–ABA form III both in solution and solid phases were studied. Molecular electrostatic potential surface has been employed to present the overall charge distribution and estimate intermolecular interactions between the form III and solvents. Hirshfeld surface analysis has been applied to visualize various molecular interactions. Besides, the effect of selected solvent properties on the dissolution behavior of m–ABA form III was examined. Finally, molecular simulations have been further applied to disclose the interactions between solute and solvent molecules. This work has guiding significance for the design and optimization of the m–ABA crystallization process.