Solvation coefficients

The thermodynamic coefficients of solvation of a solute s (whether charged or neutral) in a solvent w are the changes in thermodynamic coefficients for the process 

Qosely related are the coefficients of transfer from a dilute solution in one solvent to another, which corresponds to the process 

A Hamiltonian model for the study of these coeffidents must necessarily be at the S or BO level rather than the MM level, and so little progress has been 

---

In liquid phase reactions, the importance of the swelling properties and the related sorption capacities for the catalytic activity of ion exchangers was demonstrated. The rate coefficient of 1-butanol—acetic acid esterification [431] decreased with the degree of crosslinking in the same manner as did the water sorption capacity and the solvation coefficient of 1-butanol. A similar effect was found for the transesterification of ethyl acrylate with 1-butanol [404]. 

Thus, according to Sahai and Sverjensky, the binding constants for monovalent cations and anions can be calculated when their crystallographic ionic radii and the dielectric constant of the adsorbent are known. Moreover, an empirical equation was proposed to calculate the inner capacitance as a function of the aqueous solvation coefficient and aqueous effective radius. These two parameters depend only on the nature of the 1-1 salt, but they are independent of the adsorbent, and the C] values are listed in Table 5.20. 

The diffusion coefficients D of macromolecules in dilute solutions have values of 10 cm /s (Table 7-1). The diffusion coefficients of the proteins ribonuclease, hemoglobin, collagen, and myosin, as well as deoxyribonuclease, were measured in dilute aqueous salt solutions. They were transformed into pure water diffusion coefficients by assuming that any differences are caused by differing viscosities only, and not by changes in the asymmetry or solvation coefficients. The diffusion coefficients of macromolecules in the melt are much lower, being 10" -10 cm /s. 

This equation is treated in more detail in Section 1.2.4 in Chapter 1 and Section 4.3.1 in Chapter 4. There was no way for the estimation of the correlation volume for the application of expressions such as Equation 3.2, so that the preferential solvation coefficients, for example, for solvation of component C by the components A and B is simply defined as... 

The preferential solvation phenomenon in a ternary polymer system indicates which component, (1) or (2), is preferentially adsorbed by component (3) it is quantified by means of the preferential solvation coefficient, A. From a chromatographic point of view, adsorption or, conversely, incompatibility between solute (2) and gel matrix (3) can be detected through the coefficient K, as seen before. Therefore, both parameters, A and Kp, have a similar physical meaning in the sense that an equilibrium between a binary and a ternary phase is estabhshed and, consequently, one could try to relate them. Accordingly, it is expected that when ATp > 1 [meaning compatibility between polymer (2) and gel matrix (3)], values of A < 0 will be obtained, denoting a preferential solvation of... 

In fact, the preferential solvation coefficient. A, represents the volume of solvent (1) or polymer (2) (in ml) adsorbed by the mass (in grams) of polymer (3), and can be calculated at finite polymer composition, (f>2, by... 

Fig. 1 Plot of the preferential solvation coefficient, A, as a function of the volume fraction of polymer(2), (f>2, at three hydro-dynamic volumes, Vh = 10 (0%) 10 ( ), and 10 (AA) ml/mol for different systems (a) THF/PBD/PS and (b) Bz/PBD/ PS eluted in a,-Styragel (empty symbols) and TSK Gel Hhr (solid symbols) columns. Solid line has been calculated with equations and 03 values given in Ref. 28.

Kleintjens et al. have studied phase separation in solutions of branched polymers in relation to the relative degree of chain branching . Dondos has concluded that preferential solvation coefficients in mixed solvents are not dependent on the degree of branching. 

Solvation coefficients of ions [such as H, Ag etc.] in aqueous-organic mixtures 269 evaluation by means of the ferrocene-ferricinium couple... 

Formation constants of iodine-iodide complexes in water-acetonitrile and water- 291 ethanol mixtures solvation coefficients of Is anion... 

---