Solubility Measurement, Correlation, and Thermodynamic Study of trans-3-Hydroxycinnamic Acid in Nine Pure Solvents and (Ethanol + Ethyl Acetate) Cosolvent Mixtures at Temperatures from 293.15 to 333.15 K

Abstract

The solubility of trans-3-hydroxycinnamic acid in pure solvents (methanol, ethanol, n-propanol, isopropanol, nbutanol, isobutanol, methyl acetate, ethyl acetate, and n-propyl acetate) and (ethanol + ethyl acetate) cosolvent mixtures was measured by the gravimetric method from 293.15 to 333.15 K in normal pressure. The experimental results show that the solubility of 3-HCA(E) in alcohol solvents is greater than in ester solvents, which conforms to "like dissolves like". On this basis, the experimental result was correlated with semiempirical models (the modified Apelblat, van't Hoff, λh, Jouyban−Acree−van't Hoff equation, and combined model) and activity coefficient models (Wilson, NRTL, and UNIQUAC equation). The modified Apelblat model has the best correlation of the experimental data, with an ARD of less than 0.5% for pure solvents and cosolvent mixtures. The solvent effect was calculated by the KAT-LSER equation, showing that the hydrogen bond alkalinity of solvents−solutes (β) and the solvent self-association (δ H ) significantly influence the solubility of 3-HCA(E), accounting for 32.46 and 55.02%, respectively. Finally, the thermodynamic parameters (ΔH mix , ΔS mix , ΔG mix ,%ξ H , and %ξ TS ) were calculated. Negative values of both ΔH mix and ΔG mix indicate that the mixing process of 3-HCA(E) is exothermic and spontaneous. The Gibbs energy of the mixing process is jointly contributed by enthalpy and entropy.

Measurement and Correlation of Solubility of Glutathione in Four Binary Solvents from 278.15 to 318.15 K

“…The activity coefficient equation is widely used to describe the solid–liquid equilibrium in nonideal solutions, ignoring the influence of pressure, as expressed in , Here, x 1 represents the solubility of GSH in the binary solvent; Δ fus H , T m , and R represent the fusion enthalpy, melting point, and gas constant, respectively; and γ 1 represents the activity coefficient.…”

“…Crystallization is a widely used industrial purification method. Solubility measurements are crucial raw data for crystallization operations and can guide the selection of crystallization design parameters such as the crystallization method, solvent type, and temperature . To optimize the crystallization process, the solubility of GSH in the binary solvent systems of water and other organic solvents must be studied.…”