Luciano Lepori

Group contributions to the thermodynamic properties of non-ionic organic solutes in dilute aqueous solution

The thermodynamic properties ΔGho,ΔHho, and ΔCp,hoassociated with the transfer of non-ionic organic compounds from gas to dilute aqueous solution and the limiting partial molar properties Cpo,2 and V22 of these compounds in water are described through a simple scheme of group contributions. A distinction is made between groups made only of carbon and hydrogen, and functional groups i.e. groups containing at least one atom different from carbon and hydrogen. Each group is assigned a contribution, for each property, through a least squares procedure which utilizes only molecules containing at most one functional group. Finally, for compounds containing more than one functional group, correction parameters are evaluated as the differences between the experimental values and those calculated by means of the group contributions. The different behavior of hydrophilic compared with hydrophobic groups is discussed for the various properties. A rationale for the correction parameters, i.e. for the effects of the interactions among hydrophilic groups on the thermodynamic properties, is attempted.

Thermodynamics of binary mixtures containing oxaalkanes. Part 3. Monoethers, polyethers, acetals, orthoesters and cyclic monoethers + n-alkanes or cyclohexane

Abstract The data available in the literature for the excess Gibbs energies G E , excess enthalpies H E , activity coefficients γ ∞ i , and partial molar excess enthalpies h E,∞ i at infinite dilution, and excess heat capacities C E P of noncyclic monoethers, polyethers, acetals and orthoesters and of cyclic monoethers + n-alkanes or + cyclohexane are examined on the basis of the DISQUAC group contribution model. The interaction parameters, quasichemical and dispersive, depend on the intramolecular environment of the O atom. There is clear evidence for a steric effect exerted by the alkyl groups adjacent to the O atom, for OCO proximity effect (in acetals and orthoesters), and for a ring strain effect (in cyclic ethers). The steric effect results in a regular decrease of the quasi-chemical interaction parameters; the dispersive parameters remain constant. The proximity effect of O atoms produces a regular decrease, and the ring strain a regular increase, in both the quasi-chemical and the dispersive interaction parameters.

Partial Molar Volumes of Ionic and Nonionic Organic Solutes in Water: A Simple Additivity Scheme Based on the Intrinsic Volume Approach

AbstractPartial molar volumes at infinite dilution,

VLE and LLE of perfluoroalkane + alkane mixtures

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Isothermal liquid-vapour equilibria of mixtures containing organic compounds. 3. Excess Gibbs free energies of cyclohexane + a linear ether.☆

, in water at 25°C for organicelectrolytes and nonelectrolytes are described through a simple additivity schemebased on the intrinsic volume approach. The contributions to

Kirkwood–Buff integrals and preferential solvation in ternary non-electrolyte mixtures

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