Determination and Modeling of the Solubility of 2,4-Dimethoxybenzoic Acid in Six Pure and Isopropanol + Ethyl Acetate Mixed Organic Solvents at Temperatures From (288.15 to 323.15) K

Abstract

In our experiment, a dynamic method was taken to measure the solubilities of the 2,4-dimethoxybenzoic acid under atmospheric pressure (p = 0.1 MPa) in ethanol, npropanol, isopropanol, n-butanol, isobutanol, and ethyl acetate as well as in the isopropanol + ethyl acetate mixtures from (288.15 to 323.15) K. The experiment results have proved that the rising temperature leads to increased solubility of the 2,4-dimethoxybenzoic acid in all selected solvents. The changing model parameters in each selected solvent was recorded and calculated, respectively, during the experiments and the solid− liquid equilibrium data in pure and mixed solvents was correlated with a series equations, including the modified Apelblat equation, Wilson equation, UNIQUAC equation, and the Jouyban−Acree. During the study, the computational values were in good agreement with the experimental results according to the calculations based on all selected equations, however the modified Apelblat equation stood out to be the most suitable with the most accuracy. In addition, some thermodynamic parameters of the solution of 2,4-dimethoxybenzoic acid including dissolution enthalpy (ΔH sol ), entropy (ΔS sol ) and the Gibbs energy (ΔG sol ) were obtained via the van't Hoff analysis. The positive values ofΔH sol andΔG sol indicated that the dissolution process of dissolving 2,4-dimethoxybenzoic acid is endothermic.

Measurement and Correlation of the Solubility of Vanillic Acid in Eight Pure and Water + Ethanol Mixed Solvents at Temperatures from (293.15 to 323.15) K

“…The relative standard uncertainty of Δ fus H was estimated to be 0.02. The apparatus (TGA/DSC1/1600LF, Mettler Toledo Co., Switzerland) was calibrated with a 0.999999 mole fraction purity indium and tin sample under a nitrogen atmosphere . Vanillic acid sample (about 5 mg) was added to a hermetically sealed DSC pan, with a heating rate of 10 K·min –1 .…”

Solvent and temperature effects on the solubility of syringic, vanillic or veratric acids: Experimental, modeling and solid phase studies

“…In this work, the solubility of the selected acids was measured in water and organic solvents (methanol, ethanol, 1-propanol, 2-propanol, 2-butanone, ethyl acetate, acetonitrile, dimethylformamide -DMF, 1,2propanediol, 1,3-propanediol and 1,3-butanediol) at 298.2 K and 313.2 K. For many of the studied binary systems, no solubility data have been reported yet, but whenever possible, the new solubility data were critically compared to the data available in literature. Besides a few studies concerning veratric [16,17], vanillic [18][19][20][21], and syringic acids [22][23][24] solubility, other works focused on aromatic acids with similar structures, such as o-anisic acid (2-methoxybenzoic acid) [25], p-anisic acid (4-methoxybenzoic acid) [25], 2,4-dimethoxybenzoic acid [26], 3,5-dimethoxybenzoic acid [27] and 3,4,5-trimethoxybenzoic acid [28]. In order to obtain a more complete picture of the solid-liquid equilibrium (SLE), the melting properties of the solutes were measured by Differential Scanning Calorimetry (DSC) as well as solid phase studies were carried out by X-Ray Diffraction (XRD).…”

Solubility Determination and Thermodynamic Modeling of Glutaric Anhydride in Diverse Solvent Systems Consisting of Acetic Acid, Ethanoic Anhydride, and Tetrachloromethane from T = (278.45 to 324.45) K

“…Based on the Wilson equation, Ronon and Prausnitz developed the concept of partial composition, which introduced a parameter that reflects the characteristics of the system in the equations that is associated the partial composition with the overall composition, and proposed the NRTL equation that is widely used to predict the solid–liquid equilibrium of solute in the nonideal solution at atmospheric pressure. The NRTL is shown in eq –. − where R is the gas constant, Δ g ij means Gibbs’s energy of intermolecular interaction in solid–liquid equilibrium, and α is an empirical constant, which is usually 0.2–0.47. The ln­(γ i ) is a function of mole fraction solubility and temperature, and x i c was calculated using eq , and molar fusion enthalpy Δ fus H i and melting temperature T m of glutaric anhydride were determined by differential scanning calorimetry (DSC).…”