Studying the Thermodynamic Properties of DL-Malic Acid Acids in a Binary Mixture of Water and Tetrahydrofuran

Abstract

In This Research Studied The solubility of DL-Malic acid in Water + THF mixtures by astatic analytical technique using the acid–base titration method at temperatures ranging from 298.15 to 323.15 K and atmospheric pressure 101.3 kPa. The effects of mass fraction Tetrahydrofuran in the solvent mixtures at (0.1 to 0.95) on the solubility were studied and stirring plus settled in different times.The experimental results indicated that the solubility of DL-Malic acid in the binary solvent mixtures increases with increasing temperature and mass fraction of THF. While stirring or settling times were investigated it has no effect on the solubility in Binary solvent.The equilibrium results consisted of solubility data and tie-lines were presented in ternary phase diagrams by Matlab program. The thermodynamic properties of solution enthalpy, entropy and Gibbs free energy change of solution is calculated by using the van’t Hoff equation and Gibbs equation. The values of both the enthalpy change and the molar Gibbs free energy change of solution were positive which meaning that the dissolution of DL-malic acid into THF + water solvent mixtures is endothermic and non-spontaneous.

Keywords: Solubility, DL-Malic acid, Thermodynamic properties, Binary mixtures, Ternary system, Tetrahydrofuran, Solid–Liquid equilibrium (SLE).