Solubility of 2-Chlorophenylacetic Acid in 12 Pure Solvents from T = (273.15/283.15 to 318.15) K: Determination and Modeling

Abstract

The solubility data of 2-chlorophenylacetic acid in solid–liquid equilibrium were indispensable for a preliminary industrial application aimed at purifying and renewing. In this paper, the solubilities of 2-chlorophenylacetic acid in 12 alternative solvents (toluene, water, acetonitrile, ethylacetate, ethylbenzene, n-propanol, isopropanol, n-butanol, isobutanol, cyclohexane, 2-butanone, and acetone) at atmospheric pressure and temperatures ranging from 273.15/283.15 to 318.15 K were determined by the isothermal saturation method. Upon the analysis of the experimental data, the mole fraction solubility increased when the solution temperature increased. Generally, the solubility order in different solvents is as follows: 2-butanone > (acetone, isopropanol, ethylacetate, n-propanol, isobutanol, n-butanol) > acetonitrile > toluene > ethylbenzene > cyclohexane > water. Thermodynamic models such as the modified Apelblat equation, λh equation, Wilson model, and NRTL model were chosen to fit and correlate the obtained solubility data. Some association parameter could be obtained. The maximum value of root-mean-square deviation (RMSD) is 48.72 × 10–4, and the maximum relative mean deviation (RAD) is 1.86%. Besides, the mixing properties of the solutions were obtained, including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞), and reduced excess enthalpy (H1E,∞). The course of dissolution is spontaneous, though the study of solubility and thermodynamics was helpful to the purification process of 2-chlorophenylacetic acid.