Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The solid-liquid equilibrium behavior of P-aminobenzoic Acid Potassium (KPAB) in pure organic solvents and binary (water + isopropanol) solvents were determined over temperature range (283.15~318.15) K using a laser dynamic method. It was found that KPAB is easily dissolved in water, poly-hydroxy alcohols and amides; slightly soluble in ethyl acetate, isopropanol and n-propanol. The solubility of KPAB in both the mono and binary mixed solvents increases with the increasing temperature, whereas it decreases with the rise of mole fraction of isopropanol in binary (water + isopropanol) mixed solvents. The solubility in pure solvents was correlated by the modified Apelblat equation, and the solubility in binary mixed solvents was correlated with the modified Apelblat equation and Combined Nearly Ideal Binary Solvent/Redlich-Kister (CNIBS/R-K) model. All the models give satisfactory correlation results with the value of Average Relative Deviation (ARD) less than 2.5%. The molar enthalpy of crystallization has been calculated and the heat released in crystallization process is about 5.86 ~ 9.87 kJ*mol-1, which provide basic data for the design of KPAB crystallization process and equipment.