Enthalpies, heat capacities, and volumes of transfer of the tetrabutylammonium ion from water to aqueous mixed solvents from the point of view of the scaled-particle theory

Abstract

NICOLE DESROSIERS and JACQUES E. DESNOYERS. Can. J. Cheni. 54, 3800 (19761. The enthalpies. heat capacities, and volumes of transfer of the tetrabutjlammoniuni ion from water to urea-~+ater, 1ei.t-butyl alcohol -water, and sodium chloride -hater mixtures have been calculated at 25 C ~~s i~i g the scaled-particle theor). In general, the signs, magnitudes. and overall trends in the cosolve~lt concentration dependence of the properties are predicted from the cavit) contributions only. T h e x calculations are found to be very sensitive to the diameters chosen for the various species.For these calculations it was necessary t o liieasure with a dilatometer the coefticients of therlnal expansion of re1.r-butql alcohol-water niixtures as a function of concentration and temperature. NICOLE DESROSIERS et J A C Q U E~ E. D E \~Y E R S .Can. J. Cheni. 54. 3800 (1976). Les enthalpies, capacitis calorificl~~es et volumes de transfert du cation tCtrabutylanimoiiium de I'ea~i aux melanges eau-uree, eau -chlorure de s o d i~u n et eau-r~i.t-b~~ta!ioI ont Cte c a l c~~l e s a 25 ' C B I'aide de la theorie des particules calibrees (scalecl-particle theory). En general, les signes, les ordres de grandeur et les tendances deb dilYerentes propriet6s en fonction tie la concerltration en co\olvant sont predits h partir des tcrmes relatifs 2 la formation de cavitC seulenient. Ces calculs sont trks sensibles a u choix des diametres des dilferentes espkces en solution. Pour ces calculs il a etC nCcessaire de mesurer au moqen d'un dilatomktre les coellicients de dilatation cubiclue des melanges eau-rerr-butanol en fonction de la co~lcentratio~l et de la temperature.

Thermodynamics of transfer of glycine, diglycine, and triglycine from water to aqueous solutions of urea, glycerol, and sodium nitrate

“…It is now well recognised (12,13,(23)(24)(25)(26) that for large-sized species, the true interaction effect, i.e., AG? (int) which is A@ but free from any cavity effect, AG:(cav) (27), is a better indicator of the true picture of interactions between the solute and solvent molecules.…”

“…Moreover, though the SPT is not applicable for species other than hard spheres and for species having strong and directional interactions with solute molecules (25,30), the calculations done above might seem to be over exaggerated in the case of DG and TG. Since the diameter of the solute is not that sensitive a parameter as the diameters of cosolvent molecules (25,27) are, the SPT is now increasingly used in computing thermodynamic quantities of cavity formation of different solutes not only in different organic solvents but also in aqueous mixtures of various ionic and nonionic cosolvents (13, 23-27, 30, 31) assuming tentatively an equivalent hard sphere for each of the solute species.…”

“…Since the diameter of the solute is not that sensitive a parameter as the diameters of cosolvent molecules (25,27) are, the SPT is now increasingly used in computing thermodynamic quantities of cavity formation of different solutes not only in different organic solvents but also in aqueous mixtures of various ionic and nonionic cosolvents (13, 23-27, 30, 31) assuming tentatively an equivalent hard sphere for each of the solute species. Moreover, while Morel-Desroisers and Morel (30) have used these A@(cav) values as the guiding factor for solvation properties, we have, however, used the same, as some authors did (13, 23-27, 30, 3 I), for correcting the cavity contribution from the observed transfer free energy A@ to evaluate A@(int) values which are as shown earlier, likely to reflect the true interaction effects.…”

A surface tension approach to the salting-out of nonpolar nonelectrolytes

“…In 1969 Shoor and Gubbins (5) applied solvated salts or to polar nonelectrolytes for reascaled particle theory to the problem, and this has, sons that will be apparent. relative to the McDevit-Long formulation (MLT), w e consider the transfer, at a given concentrahad a fair measure of success (6)(7)(8)(9)(10)(11)(12). The limita-tion in ideal dilute solution, of 1 mol of nonpolar ti0n.s of all these approaches have been .~mmarised nonelectrolyte (component 3), from pure solvent by Cross (3).…”

“…If we make the approximation that the solute (molar volume V3) consists of close-packed spherical molecules in its pure state and assume the cavity area is equal to the surface area of the solute molecule (see Discussion), then and combination of eqs. [8], [9], and [l 11 yields for a 1,l-electrolyte the very simple expression [12] Tables 1 and 2. The values of R for the gases represented in Table 1 were calculated using the equilibrium diameters, dm,,, quoted by de Boer (23), and k was calculated using the equation equivalent to eq.…”