Preferential solvation of dehydroepiandrosterone acetate in (co-solvent + ethyl acetate) mixtures according to the inverse Kirkwood–Buff integrals method

Solubility and Preferential Solvation of 3-Nitrobenzonitrile in Binary Solvent Mixtures of Ethyl Acetate Plus (Methanol, Ethanol, n-Propanol, and Isopropyl Alcohol)

“…The IKBI method is valuable for calculating the preferential solvation of nonelectrolyte in mixed solvents, which describes the local solvent composition around the solute in comparison with the global solutions composition. ,,− The dealing relies upon the value of standard molar Gibbs energies of transfer of solute from pure alcohol to the ethyl acetate (1) + alcohol (2) mixtures and the excess molar Gibbs energy of mixing for the mixed solvents. As has been shown in the publications, ,,− the studies on preferential solvation can present valuable information relating to the molecular interactions.…”

“…The preferential solvation parameter of 3-nitrobenzonitrile (compound 3) by the ethyl acetate (compound 1) in ethyl acetate (1) + methanol (ethanol, n -propanol, and isopropyl alcohol) (2) mixtures is described as ,,− where x 1,3 L denotes the local mole fraction of ethyl acetate (1) in the environment near to 3-nitrobenzonitrile (3) (solvation sphere) and x 1 is the mole fraction of ethyl acetate (1) in the bulk solution. The parameter δx 1,3 > 0 denotes the excess or deficiency of ethyl acetate of the ethyl acetate (1) + methanol (ethanol, n -propanol, and isopropyl alcohol) (2) mixture in the local region.…”

“…Nevertheless, if x 1,3 L ≈ 1, then complete solvation of the solute is carried out by the ethyl acetate. The parameter δx 1,3 in the solvent mixtures may be attained from the inverse Kirkwood–Buff integrals (IKBI) for each solvent component as shown in the following equations. ,,− with here κ T denotes the isothermal compressibility of the binary mixtures (in GPa –1 ). Because of the dependence of κ T upon solvent composition, the κ T dependence on composition of a solvent mixture may be approximately obtained from individual isothermal compressibility of a component as ,,− here x i is the mole fraction of component i in the solution and κ T,i o is the isothermal compressibility of the neat solvent i with the values 1.252 GPa –1 for methanol, 1.153 GPa –1 for ethanol, 1.025 GPa –1 for n -propanol, 0.523 GPa –1 for isopropyl alcohol, and 1.207 GPa –1 for ethyl acetate at 298.15 K…”

“…The parameter D (eq ) represents the derivative of standard molar Gibbs energy of transfer of 3-nitrobenzonitrile from pure alcohol (2) to ethyl acetate (1) + alcohol (2) solutions with respect to ethyl acetate composition (in kJ·mol –1 ). The parameter Q (eq ) involves the second derivative of the excess molar Gibbs energy of mixing of the two solvents ( G 1 + 2 Exc ) with respect to the alcohol composition in the binary mixtures (kJ·mol –1 ). ,,− V cor denotes the correlation volume, and r 3 is the molecular radius of 3-nitrobenzonitrile computed with eq using N Av as the Avogadro’s number. Because of no partial molar volume of 3-nitrobenzonitrile (3) in the mixtures reported in the previous publications, here it is considered similar to that for pure 3-nitrobenzonitrile. ,− In this manner, the partial molar volume of 3-nitrobenzonitrile ( V̅ 3 ) in these solvent mixtures (cm 3 ·mol –1 ) is obtained from the molar mass (148.12 g·mol –1 ) and density (1.310 g·cm –3 ) as 113.1 cm 3 ·mol –1 .…”

“…The parameter Q (eq ) involves the second derivative of the excess molar Gibbs energy of mixing of the two solvents ( G 1 + 2 Exc ) with respect to the alcohol composition in the binary mixtures (kJ·mol –1 ). ,,− V cor denotes the correlation volume, and r 3 is the molecular radius of 3-nitrobenzonitrile computed with eq using N Av as the Avogadro’s number. Because of no partial molar volume of 3-nitrobenzonitrile (3) in the mixtures reported in the previous publications, here it is considered similar to that for pure 3-nitrobenzonitrile. ,− In this manner, the partial molar volume of 3-nitrobenzonitrile ( V̅ 3 ) in these solvent mixtures (cm 3 ·mol –1 ) is obtained from the molar mass (148.12 g·mol –1 ) and density (1.310 g·cm –3 ) as 113.1 cm 3 ·mol –1 . From this molar volume, 3-nitrobenzonitrile radius value ( r 3 ) is computed with eq as 0.355 nm. By using the mole fraction solubility data of 3-nitrobenzonitrile (Tables –), the numerical values of standard molar Gibbs energies of transfer of 3-nitrobenzonitrile from pure alcohol (2) to ethyl acetate (1) + alcohol (2) mixtures can be obtained using eq at different temperatures and are presented in Tables S2 and S3. The variations of Δ tr G 3,2→1 + 2 0 with ethyl acetate composition at different temperatures are shown in Figure S4 and correlated with eq .…”