Experimental measurements, equilibrium study and model correlation of methyl paraben in ethanol and methanol aqueous solutions from = (293.15 to 323.15) K

Abstract

Data on corresponding solid–liquid equilibrium of methyl paraben (MP) in methanol, ethanol and binary aqueous systems are essential for industrial design and further theoretical studies. By the gravimetric method, the solubility of MP in pure water and two binary mixed solvents (methanol + water, ethanol + water) were measured over the temperature range from 293.15 to 323.15 K at atmospheric pressure. According to the experimental results, it could be found that the solubility of MP in three tested pure and binary solvent systems increased with the rise of temperature at the measurable ranges. The solubility data of MP in both binary solvent systems increase with the increasing of mole fraction of methanol or ethanol. Van't Hoff equation modified Apelblat equation, Yaws equation and, λh equation model were applied to correlate the experimental solubility data of MP in pure and mixed solvent systems. Finally, the thermodynamic behavior of MP dissolution process were analyzed, and its standard molar enthalpy (ΔsolH°), Gibbs energy (ΔsolG°), and entropy (ΔsolS°) of MP dissolution in the studied systems were acquired. It was found that the dissolution processes of MP in the tested systems were non spontaneous, endothermic and entropy-driven.